This small family, including only two genera of Bats of peculiar aspect,
limited to the tropical and subtropical parts of the eastern hemisphere,
is distinguished from the _Rhinolophidæ_ by the presence of a distinct
tragus to the ear, and by the premaxillæ being cartilaginous or small and
separated from one another in front by a distinct space.
_Megaderma._[593]—Dentition: _i_ ⁰⁄₂, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃; total
28 or 26. This genus, which is represented by five species, is readily
recognised by the absence of upper incisors, the cylindrical narrow
muzzle surmounted by an erect naked cutaneous nose-leaf, the base of
which conceals the nasal orifices, by the immense connate ears with large
bifid tragi, and by the great extent of the interfemoral membrane, in
the base of which the very short tail is concealed. _M. gigas_ (Fig.
307), from Central Queensland (length of forearm 4·2 inches), is not
only the largest species of the genus but also of the suborder. _M.
lyra_, common in India (forearm 2·7 inches), has been caught in the act
of sucking the blood, while flying, from a small species of _Vesperugo_,
which it afterwards devoured, so that it is probable that the Bats of
this genus do not confine themselves to insect prey alone, but also feed,
when they can, upon the smaller species of Bats and other small mammals.
[Illustration: FIG. 307.—_Megaderma gigas._ × ½. (From Dobson, _Proc.
Zool. Soc._ 1880.)]
The Oriental _M. spasma_ and _M. lyra_ differ from the Ethiopian _M. cor_
and _M. frons_ in having two upper premolars instead of one, and also in
the shape of the frontals and nasals.
_Nycteris._[594]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total
32. This genus, of which there are seven species, differs so much from
_Megaderma_ that it may be considered the type of a separate subfamily.
As in that genus, the frontal bones are deeply hollowed out and expanded
laterally, the muzzle presents a similar cylindrical form, and the lower
jaw also projects, but the single elevated nose-leaf is absent, and
instead of it the face is marked by a deep, longitudinal, sharp-edged
groove extending from the nostrils (which are on the upper surface of
the muzzle, near its extremity) to the low band connecting the bases of
the large ears, the sides of this depression being margined as far back
as the eyes by small horizontal cutaneous appendages. All the species
resemble one another closely, and are mainly distinguished by the form
of the tragus and the size and relative position of the second lower
premolar. With the exception of _N. javanica_, they are all limited to
the Ethiopian region.
_Family_ VESPERTILIONIDÆ.
Nostrils opening by simple crescentic or circular apertures at the
extremity of the muzzle, not surrounded by distinct foliaceous cutaneous
appendages; premaxillæ small, lateral, and separated by a wide space
in front; tragus distinct. In addition to these characters, it may be
observed that the skull is of moderate size, the nasal and frontal
bones not being much extended laterally or vertically, nor furrowed by
deep depressions. The number of incisors varies from ²⁄₃ to ¹⁄₃, rarely
(in _Antrozous_ only) ¹⁄₂, premolars ³⁄₃, or ²⁄₂, or ¹⁄₂, rarely (in
_Vesperugo noctivagans_ of North America) ²⁄₃; the upper incisors are
small, separated by a wide space in the middle line, and placed in pairs
or singly near the canine; the molars are well-developed, with acute
W-shaped cusps.
This family, which may be regarded as occupying a central position in
the suborder, includes the common simple-faced Bats of all countries,
of which the well-known Pipistrelle and the Whiskered Bat (_Vespertilio
mystacinus_) may be taken as familiar types, and its species number more
than 150, or considerably more than one-third the total number of the
known species of the entire order. The various genera may be conveniently
grouped into the _Plecotine_, _Vespertilionine_, _Miniopterine_, and
_Thyropterine_ divisions.
In the _Plecotine_ division, of which the common Long-eared Bat
(_Plecotus auritus_) is the type, the crown of the head is but slightly
raised above the face-line, the outermost upper incisor is close to the
canine, and the nostrils are margined behind by grooves on the upper
surface of the muzzle, or by rudimentary nose-leaves; the ears also are
generally very large and united.
_Plecotus._[595]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total
36. Outer margin of ear-conch ending abruptly near the angle of the
mouth, the inner margin with a more or less prominent rounded projection
directed inwardly above the base; tragus very large, tapering upwards,
with a lobe at the base of its outer margin, rounded, and placed half
horizontally. This genus is represented by the European Long-eared Bat
(_P. auritus_), and _P. macrotis_, restricted to North America. The
latter is distinguished by the great size of the glandular prominences of
the sides of the muzzle, which meet in the centre above and behind the
nostrils. _P. auritus_ extends over the greater part of the Palæarctic
region, occurring in Ireland in the west and the Himalaya in the east.
_Synotus._[596]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; total 34.
This genus is distinguished from the preceding by the loss of one lower
premolar and by the outer margin of the ear being carried forwards above
the mouth and in front of the eye; it includes the European Barbastelle
Bat (_S. barbastellus_) and _S. darjilingensis_ from the Himalaya.
_Otonycteris._[597]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total
30. The reduction in the number of upper incisors readily characterises
this genus, which appears to connect the typical representatives of the
section, through _Scotophilus_, with the Vespertilionine division. It is
represented by a single species, _O. hemprichi_, from North Africa and
the Himalaya.
_Nyctophilus._[598]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃;
total 30. This and the following genera are distinguished from all the
preceding by the presence of a rudimentary nose-leaf. The present genus
contains _N. timoriensis_ of the Australian region, and _N. microtis_ of
New Guinea.
_Antrozous._[599]—Dentition: _i_ ¹⁄₂, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total
28. Readily distinguished from the other members of the whole family
by having but two lower incisors, and from the other species of the
section by the separate ears. The single species, _A. pallidus_, inhabits
California.
The _Vespertilionine_ division includes some nine-tenths of all the
representatives of the family. They are distinguished from the preceding
section by the simple nostrils, opening by crescentic or circular
apertures at the extremity of the muzzle, the generally small size of the
ears, and the absence of grooves on the forehead.
_Vesperugo._[600]—Dentition: _i_ ²⁻¹⁄₃, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂₋₃, _m_
³⁄₃; total 34, 30, or 36. This large genus comprises about one-third
of the section, and is divided into groups or subgenera, according to
the number of premolars and incisors; the latter varying from ²⁄₃ to
¹⁄₃ in the subgenera _Scotozous_ and _Rhogeëssa_, and the premolars
from ²⁄₂ to ¹⁄₂ (in the subgenus _Lasionycteris_ ²⁄₃). The Bats of
this genus are generally easily distinguished by their comparatively
thickly formed bodies, flat broad heads and obtuse muzzles, short,
broad, and triangular obtusely-pointed ears, obtuse and usually slightly
incurved tragus, short legs, and by the presence in most species of a
well-developed post-calcaral lobule. This lobule (which is supported
by a cartilaginous process derived from the calcar) may act as a kind
of adhesive disc in securing the animal’s grasp when climbing over
smooth surfaces. _Vesperugo_ probably contains the greatest number of
individuals among the genera of Chiroptera, and, with the exception of
_Vespertilio_, its species have also the widest geographical range, being
almost cosmopolitan; and one of the species, the well-known Serotine
(_V. [Vesperus] serotinus_) is remarkable as the only species of Bat
known to inhabit both the Old and the New World; one (_V. borealis_)
has been found close to the limits of the Arctic circle, and another
(_V. magellanicus_) inhabits the cold and desolate shores of the Straits
of Magellan, being doubtless the Bat referred to by Mr. Darwin in the
_Naturalist’s Voyage_. The Common Pipistrelle (_V. pipistrellus_),
ranging over the greater part of the Palæarctic region, is the best known
species.
_Chalinolobus._[601]—This genus agrees with _Vesperugo_ in the dental
formula, but is readily distinguished by the presence of a well-defined
lobe projecting near the angle of the mouth from the lower lip, and
by the unicuspidate first upper incisor. The species fall into two
subgenera—_Chalinolobus_ proper, with _p_ ²⁄₂, represented by _C. morio_
from New Zealand, Tasmania, and Australia, and three other species from
Australia; and _Glauconycteris_, with _p_ ¹⁄₂, limited to Southern
and Equatorial Africa, and known by _C. argentatus_ and two other
species, the Bats of this subgenus being especially remarkable for their
peculiarly thin membranes, traversed by very distinct reticulations and
parallel lines.
[Illustration: FIG. 308.—Head of _Scotophilus emarginatus_. (Dobson,
_Monogr. Asiat. Chiropt._)]
_Scotophilus._[602]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total
30. This genus comprises a comparatively small number of species nearly
allied to _Vesperugo_, and some of which approach so closely to the
aberrant types of the latter ranged under the subgenus _Scotozous_, as to
render the definition of the present genus almost impossible.[603] The
species are restricted to the tropical and subtropical regions of the
eastern hemisphere, though widely distributed within these limits. The
more typical species are distinguished especially by the single pair of
unicuspidate upper incisors separated by a wide space and placed close
to the canines, by the small transverse first lower premolar squeezed in
between the canine and second premolar, and, generally, by their conical
nearly naked muzzles and remarkably thick leathery membranes. _S. kuhli_
is probably the commonest species of Bat in India, and appears often on
the wing even before the sun has touched the horizon, especially when
the white-ants are swarming, feeding eagerly upon them as they rise in
the air. _S. gigas_, from Equatorial Africa, with the forearm measuring
3·4 inches, is by far the largest species. _S. albofuscus_, from the
Gambia, which is readily distinguished from the other species by its
white wings, is an aberrant form, in which the lower premolars are long
and not crowded together, and thereby so closely resembles _Vesperugo_
(_Scotozous_) _dormeri_ as to render it almost impossible to distinguish
_Scotophilus_ and _Vesperugo_. The figured species is from India.
_Nycticejus._[604]—This genus, with the same dental formula as
_Scotophilus_, is distinguished by the first lower premolar not being
squeezed in between the adjoining teeth, and by the comparatively much
greater size of the last upper molar. It includes only the common North
American _N. humeralis_ (_crepuscularis_), a small Bat scarcely larger
than the Pipistrelle. It seems, however, as pointed out by Mr. O. Thomas,
that the discovery of _Scotophilus albofuscus_ renders the generic
distinctness of _Nycticejus_ no longer tenable, and that the species
should be known as _Scotophilus humeralis_.
_Atalapha._[605]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃; total
32 or 30. The five species of this genus, which are confined to the
New World, are generally characterised by the interfemoral membrane
being more or less covered with hair (in the two commonest species, _A.
noveboracensis_ and _A. cinerea_, wholly covered), and by the peculiar
form of the tragus, which is expanded above and abruptly curved inwards.
These species have two upper premolars, of which the first is extremely
small and quite internal to the tooth-row.
_Harpyiocephalus._[606]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_
³⁄₃; total 34. This genus includes some eight species of small
Bats distinguished by their prominent tube-like nostrils and hairy
interfemoral membrane. _H. suillus_, from Java and neighbouring
islands, is the best-known species, and another closely allied (_H.
hilgendorfi_)has been described by Professor Peters from Japan. The
remaining six species are known only from the Himalaya and Tibet. All
appear to be restricted to the hill tracts of the countries in which they
are found.
_Vespertilio._[607]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total
38. Next to _Vesperugo_, this genus includes by far the largest number
of species, amounting to over forty; it has, however, rather a wider
geographical distribution in both hemispheres, one species at least being
recorded from the Navigators’ Islands. The species are easily recognised
by the peculiar character of the upper incisors, the crowns of which
diverge from each other; by the large number of premolars, of which the
second upper one is always very small; and by the oval elongated ear and
narrow attenuated tragus. In the British Isles this genus is represented
by four species, viz. Bechstein’s Bat (_V. bechsteini_); the Reddish-Gray
Bat (_V. nattereri_), of very local occurrence; Daubenton’s Bat (_V.
daubentoni_); and the Whiskered Bat (_V. mystacinus_).
_Cerivoula._[608]—This genus, which has the same dental formula as
_Vespertilio_, is distinguished by the parallel upper incisors, and the
comparatively large size of the second upper premolar. Some ten species
have been described from the Ethiopian and Oriental regions, of which _C.
picta_, from India and the Indo-Malayan sub-region, is the best-known,
being well characterised by its brilliantly coloured orange fur and
conspicuously marked membranes, which are variegated with orange and
black. This genus includes the most delicately formed and most truly
insectivorous, tropical, forest-haunting Bats, which appear to stand
as regards the species of _Vespertilio_ in a position similar to that
occupied by _Chalinolobus_ with respect to _Vesperugo_.
[Illustration: FIG. 309.—Side and front views of the head of _Cerivoula
hardwickei_. (Dobson, _Monogr. Asiat. Chiropt._)]
The _Miniopterine_ division includes only two genera, and is
characterised by the great elevation of the crown of the head above the
facial line, and also by the upper incisors being separated from the
canine and also in the middle line.
_Natalus._[609]—This genus, while having the divisional characters
mentioned above, agrees in the dental formula and its general external
form with _Cerivoula_, from which it is distinguished by the short
triangular tragus. It includes three species, restricted to South and
Central America and the West Indies; the head of _N. micropus_ being
shown in Fig. 310.
[Illustration: FIG. 310.—Head of _Natalus micropus_. × 3. (Dobson, _Proc.
Zool. Soc._ 1880.)]
_Miniopterus._[610]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total
36. In addition to the difference in the number of the teeth, this genus
is distinguished by the shortness of the first phalanx of the middle
finger and the great length of the tail, which is wholly contained
within the interfemoral membrane; it includes four species, restricted
to the eastern hemisphere. Of these the best-known, _M. schreibersi_,
is very widely distributed, being found almost everywhere throughout
the tropical and warmer temperate regions of the eastern hemisphere;
specimens from Germany, Madagascar, Japan, and Australia differing in no
appreciable respect from one another.
The last or _Thyropterine_ division, which likewise comprises only two
genera, is characterised by the presence of an additional osseous phalanx
in the middle finger and an equal number of phalanges in the toes, and
also by peculiar accessory clinging organs attached to the extremities.
_Thyroptera._[611]—Dentition: _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total
38. In the single species _T. tricolor_ of Brazil the clinging organs
have the appearance of small, circular, pedunculated, hollow discs (Fig.
311), resembling in miniature the sucking cups of cuttle-fishes, and are
attached to the inferior surfaces of the thumbs and soles of the feet.
With these the animal is enabled to maintain its hold when creeping over
smooth vertical surfaces.
[Illustration: FIG. 311.—Suctorial discs in _Thyroptera tricolor_. _a_,
Side and _b_, concave surface, of thumb-disc; _c_, foot with disc, and
calcar with projections (all much enlarged). Dobson, _Proc. Zool. Soc._
1876.]
_Myxopoda._[612]—The second genus is likewise represented only by a
single species—_M. aurita_ of Madagascar—and is distinguished from the
preceding by the characters of the teeth and the form of the ears.
The whole inferior surface of the pollex supports a large sessile
horse-shoe-shaped adhesive pad, with the circular margin directed
forwards and notched along its edge, and a smaller pad occupies part of
the sole of the foot.
_Fossil Vespertilionidæ._—It is not improbable that _Vesperugo_ is
represented in the Upper Eocene of the Paris basin by _V. parisiensis_,
which appears to be allied to _V. serotina_, although it has been
regarded by some writers as generically distinct, under the name of
_Nyctitherium_. _Vesperugo_ (_Nyctitherium_) also occurs in the Bridger
Eocene of the United States; _Nyctilestes_ from the same deposits being
an allied extinct genus. A number of European Miocene species have been
referred to _Vespertilio_, but the term in these cases must be used in
a somewhat wide sense. _Vespertiliavus_, of the Phosphorites of Central
France, differs from _Vespertilio_ in the proportions of its premolars.
_Section_ EMBALLONURINA.
Tail perforating the interfemoral membrane and appearing on its upper
surface, or produced considerably beyond the truncated membrane; the
middle pair of upper incisors generally large and close together.
_Family_ EMBALLONURIDÆ.
First phalanx of the middle finger folded (in repose) on the dorsal
surface of the metacarpal bone (except in _Noctilio_ and _Mystacops_).
Nostrils opening by simple circular or valvular apertures at the
extremity of the muzzle, not surrounded or margined by foliaceous
cutaneous appendages; tragus distinct.
The _Emballonuridæ_ are generally easily distinguished by the peculiar
form of the muzzle, which is obliquely truncated, the nostrils projecting
more or less in front beyond the lower lip; by the first phalanx of the
middle finger being folded in repose forwards on the upper surface of the
metacarpal bone; by the tail, which either perforates the interfemoral
membrane or is produced far beyond it; and by the upper incisors, which
are generally a single pair separated from the canine and also in the
middle line. The family is cosmopolitan like the _Vespertilionidæ_, but
rarely extends north or south of the thirtieth parallel of latitude.
Subfamily =Emballonurinæ=.—Tail slender, perforating the interfemoral
membrane, and appearing upon its upper surface, or terminating in it;
legs long, fibula very slender; upper incisors weak.
In the _Furipterine_ division the tail terminates in the interfemoral
membrane; the crown of the head is greatly elevated above the face-line;
the thumb and first phalanx of the middle finger are very short; and the
dentition is _i_ ²⁄₃, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃; total 38.
Represented by two genera, _Furipterus_[613] and _Amorphochilus_,[614]
each including one species of peculiar aspect; the latter distinguished
from the former by the widely separated nostrils and the great extension
backwards of the bony palate. Habitat South America.
In the typical or _Emballonurine_ division part of the tail is included
in the basal half of the interfemoral membrane, the remaining part
passing through and appearing upon its upper surface; the crown of the
head is slightly elevated; the pollex and first phalanx of the middle
finger are moderately long; and the number of the premolars is always ²⁄₂.
_Emballonura._[615]—Incisors ²⁄₃. Extremity of the muzzle more or less
produced beyond the lower lip, forehead flat. Contains some five species,
inhabiting islands from Madagascar through the Malay Archipelago to the
Navigators’ Islands.
[Illustration: FIG. 312.—Ear of _Emballonura raffrayana_, × 2. (Dobson,
_Proc. Zool. Soc._ 1878.)]
_Coleüra._[616]—Incisors ¹⁄₃. Extremity of the muzzle broad, forehead
concave. Has two species from East Africa and the Seychelles Islands.
_Rhynchonycteris._[617]—This genus is distinguished from _Coleüra_ by the
much-produced extremity of the muzzle. The single species, _R. naso_,
from Central and South America, is very common in the vicinity of streams
throughout the tropical parts of these countries; it is usually found
during the day resting on the vertical faces of rocks, or on the trunks
of trees growing over the water, and, owing to the peculiar grayish
colour of the fur covering the body and growing in small tufts from
the antebrachial membrane, so as to counterfeit the weathered surfaces
of rocks and the bark of trees, easily escapes notice. As the shades
of evening approach it appears early on the wing, flying close to the
surface of the water, and seizing the minute insects that hover over it.
_Saccopteryx._[618]—Incisors ¹⁄₃. Antebrachial membrane with a pouch
opening on its upper surface. This genus contains six species from
Central and South America. In the adult males a valvular longitudinal
opening is found on the upper surface of the membrane, varying in
position in different species. This opening leads into a small pouch (in
some species large enough to hold a pea), the interior of which is lined
with a glandular membrane secreting an unctuous substance of a reddish
colour with a strong ammoniacal odour. The presence of this sac only in
males indicates that it is a secondary sexual character analogous to the
shoulder-pouches of _Epomophorus_ and the frontal sacs of _Hipposiderus_.
It is quite rudimentary in the females.
_Taphozous._[619]—Incisors ¹⁄₂; upper pair deciduous. This genus,
represented by some ten species, inhabiting the tropical and subtropical
parts of all the eastern hemisphere except Polynesia, forms the
second group of this division, distinguished by the cartilaginous
premaxillaries, deciduous upper incisors, and the presence of only
two lower incisors. Most of the species have a peculiar glandular sac
(Fig. 313) placed between the angles of the lower jaw. This is a sexual
character, for, while always more developed in males than in females, in
some species, although distinct in the male, it is quite absent in the
female. An open gular sac is wanting in both sexes in _T. melanopogon_,
but about its usual position the openings of small pores may be seen, the
secretion exuding from which probably causes the hairs to grow very long,
forming the black beard found in many male specimens of this species.
[Illustration: FIG. 313.—Heads of _Taphozous longimanus_, showing
relative development of gular sacs in male and female. (Dobson, _Proc.
Zool. Soc._ 1873.)]
In the _Diclidurine_ division there is but a single genus, represented by
two species.
_Diclidurus._[620]—Dentition: _i_ ¹⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃; total
32. Both species are from the Neotropical region, the typical _D.
albus_ ranging as far north as Central America. This Bat resembles the
species of _Taphozous_ in the form of the head and ears, but, besides
other characters, differs from all other Bats in possessing a peculiar
pouch, opening on the centre of the inferior surface of the interfemoral
membrane; the extremity of the tail enters this, and perforates its
fundus.
The _Noctilionine_ division is likewise represented only by a single
genus, with two species. This genus connects the present with the
following family, possessing characters common to both, but also so many
remarkable special peculiarities as almost to warrant the formation of a
separate family for its reception.
_Noctilio._[621]—Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total
28. The two species _N. leporinus_ and _N. albiventer_ inhabit Central
and South America. The typical _N. leporinus_ is a Bat of very curious
aspect, with strangely folded lips, erect cutaneous processes on the
chin, and enormous feet and claws. The first upper incisors are close
together, and so large as to conceal the small outer ones, while in the
lower jaw there is one pair of small incisors. This apparent resemblance
to a Rodent actually led Linnæus to remove this species from the Bats and
place it in the Rodents. This Bat is remarkable for feeding on fish—a
circumstance which has only recently been fully authenticated.
The remaining genus of this subfamily is regarded as representing another
division, which may be known as the _Rhinopomatine_ division.
_Rhinopoma._[622]—This genus, represented by the single species _R.
microphyllum_, might also be elevated to the rank of a family, for it is
difficult to determine its exact affinities, a kind of cross relationship
attaching it to the _Nycteridæ_ on the one hand and to this family,
in which it is here placed provisionally, on the other. This species,
distinguished from all other Microchiroptera as well by the presence of
two phalanges in the index finger as by its remarkably long and slender
tail projecting far beyond the narrow interfemoral membrane, inhabits
the subterranean tombs in Egypt and deserted buildings generally from
North-East Africa to Burma.
[Illustration: FIG. 314.—Skull of _Rhinopoma microphyllum_. × 2. (Dobson,
_Monogr. Asiat. Chiropt._)]
Subfamily =Molossinæ=.—Tail thick, produced far beyond the posterior
margin of the interfemoral membrane (except in _Mystacops_); legs short
and strong, with well-developed fibula; upper incisors strong. This
subfamily includes all the species of _Emballonuridæ_ with short and
strong legs and broad feet (whereof the first toe, and in most species
the fifth also, is much thicker than the others, and furnished with long
curved hairs), well-developed callosities at the base of the thumbs,
and a single pair of large upper incisors occupying the centre of the
space between the canines. In all the species the feet are free from the
wing-membrane, which folds up perfectly under the forearm and legs; the
interfemoral membrane is retractile, being movable backwards and forwards
along the tail, and this power of varying its superficial extent must
confer upon these Bats great dexterity in quickly changing the direction
of their flight, as when obliged to double in pursuing their swift
insect prey, which their extremely expansible lips evidently enable them
to secure with ease. Like the preceding subfamily, the genera may be
arranged in divisions, of which there are two.
The _Molossine_ division is characterised by the production of the tail
beyond the posterior margin of the interfemoral membrane; it includes
three genera.
_Chiromeles._[623]—Dentition: _i_ ¹⁄₁, _c_ ¹⁄₁, _p_ ¹⁄₂, _m_ ³⁄₃; total
26. Hallux much larger than the other toes and separable from them, ears
separate. This genus is represented by a single species, _C. torquatus_,
of large size (forearm 3·1 inches) and peculiar aspect, inhabiting the
Indo-Malayan sub-region. This Bat is nearly naked, a collar only of
thinly spread hairs half surrounding the neck; and is further remarkable
for its enormous throat-sac and curious nursing-pouches. The former
consists of a great semicircular fold of skin forming a deep pouch round
the neck beneath, and concealing the orifices of large subcutaneous
pectoral glands, which discharge an oily fluid of insufferably offensive
smell. The nursing-pouch is formed on each side by an extension of a fold
of skin from the side of the body to the inferior surfaces of the humerus
and femur. In the anterior part of this pouch the mammæ are placed.
_Molossus._[624]—Dentition: _i_ ¹⁄₁₋₂, _c_ ¹⁄₁, _p_ ¹⁻²⁄₁, _m_ ³⁄₃;
total 24 or 28. Upper incisors close together in the middle line.
There are some ten species, restricted to the tropical and subtropical
regions of the New World. The woodcut of the head of _M. glaucinus_
(Fig. 315) exhibits the general physiognomy of the Bats of this genus.
_M. obscurus_, a small species, is very common in tropical America. It
inhabits the hollow trunks of palms and other trees, and also the roofs
of houses. The males and females live apart (as, indeed, appears to be
the case in most, if not in all, species of Bats). In the hollow trunk
of a palm two colonies were discovered, one consisting of from 150 to
200 individuals, exclusively males, while the other was composed almost
entirely of females.
[Illustration: FIG. 315.—Head of _Molossus glaucinus_. (Dobson, _Proc.
Zool. Soc._ 1876.)]
_Nyctinomus._[625]—Dentition: _i_ ¹⁄₃₋₂, _c_ ¹⁄₁, _p_ ²⁻¹⁄₂, _m_ ³⁄₃;
total 32 or 28. Upper incisors separated in the middle line. The
genus contains about twenty-five species, inhabiting the tropical and
subtropical parts of both hemispheres. The lips of the Bats of this genus
are even more expansible than in _Molossus_, in many of the species (as
in the woodcut of the head of _N. macrotis_, Fig. 316) showing vertical
wrinkles. _N. tæniotis_, one of the largest species, alone extends into
Europe, and has been taken as far north as Switzerland. _N. johorensis_,
from the Malay Peninsula, is remarkable from the extraordinary form of
its ears. _N. brasiliensis_ is nearly as common as _Molossus obscurus_
in tropical America, and extends farther north (California) and south
than that species.
In the _Mystacopine_ division the tail perforates the interfemoral
membrane and appears upon the upper surface.
[Illustration: FIG. 316.—Head of _Nyctinomus macrotis_. (Dobson, _Proc.
Zool. Soc._ 1876.)]
_Mystacops._[626]—This genus includes only _M. tuberculatus_ of New
Zealand, where, together with _Chalinolobus tumorio_, it represents the
whole indigenous mammalian fauna of the islands. There are three distinct
phalanges in the middle finger; the greater part of the wing-membrane is
exceedingly thin, but a narrow portion along the forearm, the sides of
the body, and the legs is remarkably thick and leathery; beneath this
thickened portion the wings are folded. With the wings thus encased, this
species is the most quadrupedal of Bats. Other peculiarities of structure
are found in the remarkable form of the claws of the thumbs and toes,
which have each a small talon projecting from its concave surface near
the base, also in the sole of the foot and inferior surface of the leg,
as shown in Fig. 317. The plantar surface, including the toes, is covered
with soft and very lax integument deeply wrinkled, and each toe is marked
by a central longitudinal groove with short grooves at right angles to
it. The lax wrinkled integument is continued along the inferior flattened
surface of the ankle and leg. These peculiarities appear to be related to
climbing habits in the species.
[Illustration: FIG. 317.—Pollex and leg and foot of _Mystacops
tuberculatus_, enlarged. (Dobson, _Proc. Zool. Soc._ 1876.)]
_Fossil Emballonuridæ._—In the cavern-deposits of Madras remains of
the existing _Taphozous saccolæmus_ are not uncommon; while in the
corresponding beds of Brazil bones of a _Molossus_, probably referable
to _M. temmincki_, now inhabiting the same region, are met with. It has
been suggested that remains from the Upper Eocene Phosphorites of Central
France may indicate the existence of the genus _Taphozous_ at that early
epoch.
_Family_ PHYLLOSTOMATIDÆ.
Middle finger with three well-developed bony phalanges; first phalanx
of the middle finger short; nostrils in the front part of the cutaneous
nasal appendages, or opening by simple apertures at the extremity of
the muzzle; chin with warts or erect cutaneous ridges; premaxillæ well
developed, united in front.
The members of this family are readily distinguished by the third phalanx
in the middle finger, associated either with distinct cutaneous nasal
appendages, or with well-developed first upper incisors, or with both.
Unlike the _Rhinolophidæ_, their eyes are generally large; and the tragus
is well developed, maintaining almost the same form throughout the
species, however much the other parts of the body may vary. The fur is of
a dull colour, and the face and back (in the _Stenodermatine_ division
especially) are often marked with white streaks, as in the _Pteropodidæ_,
of which these Bats take the place in the western hemisphere. A few
species, probably all those with the tail and interfemoral membrane well
developed, feed principally on insects, while the greater number of the
species of the _Vampirine_ and _Glossophagine_ divisions appear to live
on a mixed diet of insects and fruits; and the _Desmodontine_ division,
of which two species only are known, are true blood-suckers, and have
their teeth and intestinal tract specially modified in accordance with
their habits. The family is restricted to the tropical and subtropical
parts of Central and South America.
Subfamily =Chilonycteriinæ=.—Nostrils opening by simple apertures at the
extremity of the muzzle in front, not margined by a distinct nose-leaf;
chin with expanded leaf-like appendages. It includes two genera.
[Illustration: FIG. 318.—Head of _Mormops blainvillei_. (Dobson, _Cat.
Chiropt. Brit. Mus._)]
_Chilonycteris._[627]—Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃, _m_ ³⁄₃;
total 34. The crown of the head is moderately elevated above the facial
line, and the basicranial axis is almost in the same plane as the facial.
There are about half a dozen species.
_Mormops._[628]—The two species of this genus are distinguished from
_Chilonycteris_ by the great elevation of the crown of the head above
the line of the face, as well as by the basicranial plane being nearly
at right angles to the facial. Both species are noticeable for their
peculiar physiognomy, as is shown in the accompanying woodcut (Fig. 318).
Subfamily =Phyllostomatinæ=.—Nostrils opening on the upper surface of
the muzzle, the nasal apertures more or less surrounded or margined by
well-developed cutaneous appendages, forming a distinct nose-leaf; chin
with warts. The numerous genera, most of which can only be mentioned here
by name, may be arranged under four divisions.
In the first or _Vampirine_ division the muzzle is long and narrow in
front; the distance between the eyes is generally less than, rarely equal
to, that from the eye to the extremity of the muzzle; the nose-leaf
is well developed, horse-shoe shaped in front, and lanceolate behind;
interfemoral membrane well developed; tail generally distinct, rarely
absent; inner margin of the lips not fringed. The dentition is: _i_
²⁄₂₋₁, _c_ ¹⁄₁, _p_ ²⁄₂₋₃, _m_ ³⁄₃; total 32. The cusps of the upper
molars are usually well developed, and arranged in a W. Nearly all the
species of this division appear to be insectivorous, so that the name
applied to them must not be considered as having any relation to their
habits. _Vampyrus spectrum_, a large Bat inhabiting Brazil, of forbidding
aspect, which was long considered by naturalists to be sanguivorous
in its habits, and named accordingly by Geoffroy, has been shown by
the observations of modern travellers to be mainly frugivorous, and is
considered by the inhabitants of the countries in which it is found to
be perfectly harmless. It is the largest Bat in America, the length of
the forearm being 4·2 inches. _Otopterus waterhousei_ appears to prey
occasionally on small species of Bats, like _Megaderma lyra_ of the
eastern hemisphere, which it resembles in many respects.
_Lonchorhina_,[629] _Otopterus_,[630] _and Dolichophyllum_.[631]—These
three genera are characterised by the tail continuing to the hinder
margin of the interfemoral membrane. _Lonchorhina_ is represented by the
single species _L. aurita_, in which the nose-leaf is much elongated, and
the ear-conch and tragus are unusually large.
_Vampyrus_,[632] _etc._—In all the remaining genera of this division the
tail perforates the interfemoral membrane, so as to appear upon its upper
surface. These genera are _Vampyrus_, _Lophostoma_, _Micronycteris_,[633]
_Trachyops_, _Phylloderma_, _Phyllostoma_, _Anthorhina_,[634] _Mimon_,
_Hemiderma_[635] and _Rhinophylla_; all, with the exception of the last,
being distinguished from one another chiefly by the form of the skull
and the presence or absence of the second lower premolar. _Trachyops_,
_Phylloderma_, and the three last-named genera are each represented by a
single species. _Phyllostoma hastatum_, in which the forearm has a length
of 3·2 inches, and next in point of size to _Vampyrus spectrum_, is a
well-known species in South America; _P. elongatum_ (Fig. 319) differs
in its smaller size and much larger nose-leaf. _Hemiderma brevicauda_
is a small species, which forms a connecting link between this and the
next division. _Rhinophylla pumilio_, the smallest known species of the
family, is further distinguished by the narrowness of its molars, which
do not form W-shaped cusps, and by the very small size of the last upper
molar; characters connecting it with the _Stenodermatine_ division.
[Illustration: FIG. 319.—Head of _Phyllostoma elongatum_. (From Dobson,
_Proc. Zool. Soc._ 1866.)]
In the second or _Glossophagine_ division of the subfamily the muzzle
is long and narrow; the tongue remarkably long and extensible, much
attenuated towards the tip, and beset with very long filiform recurved
papillæ; lower lip with a wide groove above, and in front margined by
small warts; nose-leaf small; tail short or absent. Dentition: _i_ ¹⁄₁,
_c_ ²⁄₂, _p_ ²⁻³⁄₃₋₂, _m_ ²⁄₃₋₂; teeth very narrow; molars with narrow
W-shaped cusps, sometimes indistinct or absent; lower incisors very small
or deciduous.
The ten species included in this division are arranged under seven
genera,[636] distinguished principally by differences in the form and
number of the teeth and the presence or absence of the zygomatic arch.
The form and position of the upper incisors are extremely variable.
In _Glossophaga_ and _Phyllonycteris_ the upper incisors form, as in
the _Vampyrine_ division, a continuous row between the canines; in
_Monophylla_ and _Leptonycteris_[637] they are separated into pairs by
a narrow interval in front; while in _Lonchoglossa_, _Glossonycteris_,
and _Chœronycteris_ they are widely separated and placed in pairs near
the canines. In the first four genera the lower incisors are present (at
least up to a certain age), while in the last three they are deciduous
even in youth. The zygomatic arch is wanting in _Phyllonycteris_,
_Glossonycteris_, and _Chœronycteris_.
The typical species is _Glossophaga soricina_, which so closely resembles
_Hemiderma brevicauda_, both in external form and dentition, that it has
frequently been confounded with it. Its long fimbriated tongue, which
it possesses in common with other species of the division, led Spix to
describe it as a blood-sucker, believing that this organ was used to
increase the flow of blood. This view is, however, without foundation,
and from later observations it is evident that the peculiarly shaped
tongue is used by the animal to lick out the pulpy contents of fruits
having hard rinds. The food of the species of this division appears to
consist of both fruit and insects, and the long tongue may also be used
for extracting the latter from the deep corollæ of certain flowers. This
type of tongue is shown in the woodcut of the head of _Chœronycteris_
(Fig. 320); and it is paralleled among the Megachiroptera by the
Carponycteriine _Pteropodidæ_.
[Illustration: FIG. 320.—Head of _Chœronycteris mexicana_, showing
fimbriated tongue. (Dobson, _Cat. Chiropt. Brit. Mus._)]
The _Stenodermatine_ division is characterised by the muzzle being very
short and generally broad in front, the distance between the eyes nearly
always exceeding (rarely equal to) that from the eye to the extremity
of the muzzle; nose-leaf short, horse-shoe shaped in front, lanceolate
behind (except in _Brachyphylla_ and _Centurio_); interfemoral membrane
always concave behind; tail none; inner margin of the lips fringed
with conical papillæ. Dentition: _i_ ²⁄₂₋₁, _p_ ²⁄₂, _m_ ³⁻²⁄₃₋₂; the
number of the molars being either ³⁄₃, ²⁄₃, or ²⁄₂ in different species;
premolars and molars very broad (except in _Sturnira_), the latter with
concave or flat crowns margined externally by raised cutting-edges.
Although the members of this division are usually distinguished from
those of the Vampirine division by the peculiar shortness and breadth of
the muzzle and the form of the molars, yet certain species of the latter
closely resemble those of the former in external appearance, agreeing
almost absolutely in the form of the nose-leaf, of the ears and tragus,
and of the warts on the chin. These resemblances indicate that, while
the form of the teeth and jaws has become modified to suit the nature of
the food, the external characters, being but slightly affected by this
cause, have remained much the same. The food of these Bats appears to
be wholly or in great part fruit. The twenty species have been grouped
into nine genera, distinguished by the form of the skull and teeth.
_Artibeus_, with six species, includes the well-known frugivorous Bat,
_A. perspicillatus_. Waterton believed that _A. planirostris_, a common
Bat in British Guiana, usually found in the roofs of houses, and now
known to be frugivorous, was the true blood-sucking Vampire. _Stenoderma
achradophilum_, found in Jamaica and Cuba, associated with _Artibeus
perspicillatus_, from which it is scarcely distinguishable externally
except by its much smaller size, differs altogether in the absence of
the horizontal plate of the palatal bones. _Sturnira lilium_, while
agreeing with the above in the form of the nose-leaf and ears, differs
from all the species of the family in its longitudinally-grooved molars,
which resemble those of the _Pteropodidæ_ more closely than those of
any other Bats; and the presence of tufts of long differently coloured
hairs over glands in the sides of the neck shows another common character
still more remarkable, which can scarcely be considered the result of
adaptive change. _Centurio senex_ is the type of a genus distinguished
from _Stenoderma_ and other genera of this division by the absence
of a distinct nose-leaf; its facial aspect, as shown in Fig. 321, is
altogether bizarre.
[Illustration: FIG. 321.—Head of _Centurio senex_. (Dobson, _Cat.
Chiropt. Brit. Mus._)]
In the last or _Desmodont_ division the muzzle is conical and short;
there is a distinct nose-leaf; the interfemoral membrane is very
short; and the tail is wanting. Dentition: _i_ ¹⁄₂, _c_ ¹⁄₁, _p_ ²⁄₃,
_m_ ¹⁻⁰⁄₁₋₀; total 24 or 20. Upper incisors very large, trenchant,
occupying the whole space between the canines; premolars very narrow,
with sharp-edged longitudinal crowns; molars rudimentary or wanting;
stomach greatly elongated, intestiniform. There are only two genera, the
single species of each of which are the true blood-sucking Vampires.
They appear to be confined chiefly to the forest-clad parts, and their
attacks on men and other warm-blooded animals were noticed by some of
the earliest writers. Thus Peter Martyr (Anghiera), who wrote soon after
the conquest of South America, says that in the Isthmus of Darien there
were Bats which sucked the blood of men and cattle when asleep to such a
degree as to kill them. Condamine, a writer of the eighteenth century,
remarks that at Borja (Ecuador) and in other places they had entirely
destroyed the cattle introduced by the missionaries. Sir Schomburgk
relates that at Wicki, on the river Berbice, no fowls could be kept on
account of the ravages of these creatures, which attacked their combs,
causing them to appear white from loss of blood. Although these Bats
were known thus early to Europeans, the species to which they belonged
were not determined until about sixty years ago, several of the large
frugivorous species having been wrongly set down as blood-suckers and
named accordingly; and it fell to the lot of Darwin to determine at least
one of the blood-sucking species, the following being his account of the
circumstances under which the discovery of the sanguivorous habits of
_Desmodus rufus_ was made: “The Vampire Bat is often the cause of much
trouble by biting the horses on their withers. The injury is generally
not so much owing to the loss of blood as to the inflammation which
the pressure of the saddle afterwards produces. The whole circumstance
has lately been doubted in England; I was therefore fortunate in
being present when one was actually caught on a horse’s back. We were
bivouacking late one evening near Coquimbo, in Chili, when my servant,
noticing that one of the horses was very restive, went to see what was
the matter, and, fancying he could detect something, suddenly put his
hand on the beast’s withers and secured the Vampire.”
These Bats present, in the extraordinary differentiation of the
manducatory and digestive apparatus, a departure from the type of
other members of the family unparalleled in any of the other orders of
Mammalia, standing apart from all other mammals as being fitted only
for a diet of blood, and capable of sustaining life upon that alone.
Travellers describe the wounds inflicted by the large sharp-edged
incisors as similar to those caused by a razor when shaving: a portion of
the skin being shaved off and a large number of severed capillary vessels
thus exposed, from which a constant flow of blood is maintained. From
this source the blood is drawn through the exceedingly narrow gullet—too
narrow for anything solid to pass—into the intestine-like stomach, whence
it is probably gradually drawn off during the slow process of digestion,
while the animal, sated with food, is hanging in a state of torpidity
from the roof of a cave or the inner side of a hollow tree.
[Illustration: FIG. 322.—Head of Vampire Bat (_Desmodus rufus_).]
_Desmodus._[638]—No true molar, and no calcar. The Common Vampire (_D.
rufus_) is widely spread over the tropical and subtropical parts of
Central and South America from Oaxaca to Southern Brazil and Chili. It is
a comparatively small species, a little larger than the common Noctule,
the head and body being about 3 inches in length, the forearm 2½, with a
remarkably long and strong thumb; it is destitute of a tail, and has a
peculiar physiognomy, well represented in Fig. 322. The body is covered
with rather short fur of a reddish-brown colour, but varying in shade;
the extremities of the hairs being sometimes ashy. The teeth are peculiar
and admirably adapted for the purposes for which they are employed. The
upper incisor is greatly enlarged, and of somewhat triangular shape (Fig.
323); the canine, although smaller than the incisor, is large and sharp;
but the cheek-teeth are very small, with laterally compressed crowns
rising but slightly above the level of the gum, their longitudinally
disposed cutting-edges being continuous with the base of the canine and
with each other. The lower incisors are small, bifid, and separated from
the canine, with a space in front. The lower cheek-teeth are narrow, like
those in the upper jaw, but the anterior tooth is slightly larger than
the others, and separated by a small space from the canine. Behind the
lower incisors the jaw is deeply hollowed out to receive the extremities
of the large upper incisors. The exceedingly narrow œsophagus opens at
right angles into the slender, intestine-like stomach, which almost
immediately terminates on the right, without a distinct pylorus, in the
duodenum, but on the left forms a greatly elongated fundus, bent and
folded upon itself, appearing at first sight like part of the intestines.
This cardiac extremity of the stomach is, for a short distance, to the
left of the entrance of the œsophagus, still very narrow, but soon
increases in size, till near its termination it attains a diameter quite
three times that of the short pyloric portion. The length of this cardiac
diverticulum of the stomach appears to vary from 2 to 6 inches, the size
in each specimen probably depending on the amount of food obtained by the
animal before it was captured.
[Illustration: FIG. 323.—Dentition of _Desmodus rufus_. _a_, Front view
of upper teeth; _b_, left lateral view of upper and lower teeth.]
_Diphylla._[639]—A small true molar in each jaw, and a rudimentary
calcar. The single species _D. ecaudata_ inhabits Brazil, and appears to
be much less abundant than _Desmodus rufus_, from which, in addition to
the characters already mentioned, it is distinguished by its slightly
smaller size, the absence of a groove in the front of the lower lip,
the non-development of the interfemoral membrane in the centre, and the
peculiar form of the lower incisors, which are much expanded in the
direction of the jaws and pectinated, forming a semicircular row touching
each other, the outer pair being wider than the inner ones, and having
six notches, the inner pair having only three notches.
_Fossil Phyllostomatidæ._—Remains of _Vampyrus spectrum_, as well as of
several species of _Phyllostoma_ or closely allied types, are found in
the cavern deposits of Brazil. The mandible of a large Bat from the Upper
Eocene Phosphorites of Central France, described as _Necromantis_, has
been referred to this family—a determination which, if confirmed, will be
of great interest from a distributional point of view.
_Bibliography of Chiroptera._—G. E. Dobson, _Catalogue of the
Chiroptera in the Collection of the British Museum_, 1878,
including descriptions of all the species of Bats then known;
subsequent papers by the same author in _Rep. Brit. Assoc._,
_Proc. Zool. Soc._, _Ann. Mag. Nat. Hist._, and _Bull. Soc.
Zool. de France_; by Peters in _Monatsb. Akad. Wiss. Berlin_;
by O. Thomas in _Ann. Mag. Nat. Hist._, _Proc. Zool. Soc._,
and _Ann. Mus. Genova_; and by J. Scully in _Ann. Mag. Nat.
Hist._ and _Journ. As. Soc. Bengal_; H. A. Robin, _Recherches
Anatomiques sur les Mammifères de l’Ordre des Chiroptères_,
Paris, 1881; W. T. Blanford, “Notes on Indian Chiroptera,”
_Journ. As. Soc. Bengal_, vol. lviii. (1888). See also papers
by Jentink, Bocage, and others.
CHAPTER XIV
THE ORDER PRIMATES
This order in the system of Linnæus includes Man, the Monkeys, the
Lemurs, and the Bats. By common consent of all zoologists the last-named
animals have been removed into a distinct order; but with regard to the
association of the others there has been, and still is, much difference
of opinion.
That all the Monkeys, from the highest Anthropoid Apes to the lowest
Marmosets, form a natural and tolerably homogeneous group seems never
to have been questioned; but whether the Lemurs on the one hand and Man
on the other should be united with them in the same order are points of
controversy. If, in accordance with the traditional views of zoologists,
the former are still considered to be members of this order, they must
form a suborder apart from all the others, with which they have really
very little in common except the opposable hallux of the hind foot, a
character also met with in the Opossums, and which is therefore of very
secondary importance.[640]
Using the term Primates in this wider sense it is not easy to give
any precise definition of the order. The dentition is diphyodont and
heterodont; the number of incisors being very generally ²⁄₂, and that
of the molars, with the exception of the _Hapalidæ_, being ³⁄₃. The
cheek-teeth are adapted for grinding, the molars being more complex than
the premolars, and usually having four main tubercles, which may be
either subconical or more or less compressed. The orbit is invariably
surrounded by a ring of bone; the clavicles are well developed; and the
radius and ulna are never united. The scaphoid and lunar of the carpus,
and commonly also the centrale, remain distinct from one another. There
are usually five digits furnished with well-developed nails in both
the manus and the pes; but the pollex may be rudimentary or wanting.
The hallux, except in Man, is opposable to the other digits, and has a
flat nail (absent in _Simia_); and the pollex, when present, is usually
also more or less opposable. The terminal phalanges of the digits are
flattened (except in the second digit of the pes of the Lemuroidea), and
not cleft at their extremities. The fingers and toes generally do not
taper towards their extremities, but (except in _Chiromys_) are dilated,
flattened, and rounded at their tips. The humerus has no entepicondylar
foramen, nor the femur a third trochanter. In the alimentary canal
(Fig. 324) the stomach is generally simple, although sacculated in the
subfamily _Semnopithecinæ_ of the _Cercopithecidæ_; and there is always
a cæcum, which is generally of large size. The placenta may be either
non-deciduous, or discoidal and deciduous. There are always two mammæ in
the pectoral region, except in _Chiromys_; and the testes descend into a
scrotum.
[Illustration: FIG. 324.—Alimentary canal of _Galago_, the greater part
of the small intestine being omitted. _d_, duodenum; _i_, ileum; _cm_,
cæcum; _r_, rectum.]
The Lemuroidea are decidedly low in the scale of organisation, their
placentation being of a lower type than that of the Insectivora; and all
the Primates retain generalised features in their pentadactylate limbs
and more or less bunodont cheek-teeth. In respect to cerebral characters
and other features the higher representatives of the order have, however,
acquired a specialisation clearly indicating their right to occupy
the highest position in the animal kingdom. So far as the available
material admits of forming an opinion, fossil forms appear to indicate
an intimate connection between the Lemuroidea and Insectivora, so that
in some cases it is almost impossible to determine whether an extinct
type should be referred to the former or to the latter group. It is
noteworthy that while in all existing Primates the upper molars are of
a quadrituberculate type, in the extinct Lemuroid genus _Anaptomorphus_
they are trituberculate.
_Suborder_ LEMUROIDEA.
The Latin term _Lemur_ was applied by Linnæus to the typical
representatives of the present group of Primates, having been suggested
by the nocturnal habits and strange ghost-like appearance of some of
its members. As these animals had previously no vernacular appellation
in English, this name has been generally adopted, and is now completely
anglicised, making “Lemurs” in the plural. The French call them _Makis_,
and the Germans _Halbaffen_, in allusion to their forming a transition
from monkeys to ordinary quadrupeds. For the same reason they are called
_Prosimiæ_ by some systematic writers. When the name was bestowed by
Linnæus only five species were known, of which one, _L. volans_, Linn.
(_Galeopithecus volans_ of modern writers), is now removed by common
consent from the group. Notwithstanding the discovery of many new and
curious forms, the Lemurs remain a very natural and circumscribed
division of the animal kingdom, though no longer considered a single
genus, but divided up into many genera and even families.
The existing species are not numerous, and do not diverge widely in their
organisation or habits, being all of small or moderate size, all adapted
to an arboreal life, climbing with ease, and, as they find their living,
which consists of fruits, leaves, birds’ eggs, small birds, reptiles, and
insects, among the branches of the trees, they rarely have occasion to
descend to the ground. None are aquatic, and none burrow in the earth.
Many of the species, although by no means all, are nocturnal in their
habits, spending the day in sleeping in holes, or rolled up in a ball,
perched on a horizontal branch, or in the fork of a tree, and seeking
their food by night. Their geographical distribution is very peculiar; by
far the larger proportion of species, including all those to which the
term “Lemur” is now especially restricted, being exclusively inhabitants
of Madagascar, where they are so abundant and widely distributed that
it is said by M. Grandidier, who has contributed more than any other
traveller to enrich our knowledge of the structure and manners of these
animals, that there is not a little wood in the whole island in which
some of them cannot be found. From Madagascar as a centre a few species
less typical in character extend through the African continent westward
as far as Senegambia, and others are found in the Oriental region as far
east as the Philippine Islands and Celebes.
The following are the essential characters by which the suborder as a
whole is distinguished from the Anthropoidea. Skull with the orbit
opening freely into the temporal fossa beneath the postorbital bar
(except in _Tarsius_); and the lachrymal foramen situated externally to
the margin of the orbit (Fig. 327). The pollex and hallux are always
well developed, the latter being especially large; the second or index
digit of the manus may be rudimentary; while in the pes the second digit
invariably terminates in a long pointed claw. The cerebral hemispheres do
not completely overlap the cerebellum, and are but slightly convoluted.
The uterus is bicornuate. The placenta is non-deciduate, and either
diffused or bell shaped—the whole of the chorion except the cephalic
pole being covered with villi; and the allantois is of very great size.
There may be abdominal mammæ. Except in _Chiromys_, the first pair of
upper incisors are separated in the middle line. In marked contrast to
the Anthropoidea, the middle or transverse portion of the colon is almost
always folded or convoluted on itself. (See Fig. 324.)
In subdividing the group for the purpose of a more detailed description
of the different animals of which it is composed it must first be noted
that there are two very aberrant forms, each represented by a single
species—the little _Tarsius_ of the Indian archipelago, and the singular
_Chiromys_ or Aye-aye, which, though an inhabitant of Madagascar, the
headquarters of the suborder, and living in the same forests and under
the same external conditions as the most typical Lemurs, exhibits a most
remarkable specialisation in the structure of its limbs and teeth, the
latter being modified so as to resemble, at least superficially, those of
the Rodents, in which order it was once placed. The differences between
these two forms and the remaining Lemurs are so great that the whole
suborder naturally divides itself into three families, the first of which
may be again divided into four subfamilies.
_Family_ LEMURIDÆ.
Upper incisors two on each side, small and separated by an interval in
the middle line. Upper canine large, conical, compressed, and pointed.
Premolars two or three, molars three on each side above and below, with
numerous more or less pointed cusps. In the front of the lower jaw are
on each side two or three closely approximated, long, slender teeth
lying almost horizontally and projecting forwards. These are generally
considered to represent the incisors and canine, but there is some doubt
about their homologies, and they may be all considered as incisors, the
canine being absent. The first lower premolar larger than those behind
it, and shaped like a canine, of which it performs the function (Fig.
327). The orbit and temporal fossa widely continuous beneath the bar
of bone (formed by the frontal and jugal) constituting the posterior
boundary of the former cavity. The fibula well developed and distinct
from the tibia. All the digits of both feet (except the second of the
hind foot) with flat nails, and corresponding form of ungual phalanges.
Subfamily =Indrisinæ=.—The dentition of the adult consists of thirty
teeth, usually expressed by the formula _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ²⁄₂, _m_
³⁄₃; but, as indicated above, they may be _i_ ²⁄₂, _c_ ¹⁄₀, _p_ ²⁄₂, _m_
³⁄₃. In the milk-dentition there are twenty-two teeth, the true molars
of course not being represented, but there are two additional teeth in
the fore part of the lower jaw which have no successors in the permanent
series. Hind limbs greatly developed, but the tarsus normal. Hallux of
large size, and very opposable. The other toes united at their base by a
fold of skin, which extends as far as the end of the first phalanx. Mammæ
two, pectoral. Cæcum very large, and colon extremely long and spirally
coiled.
The animals of this group are, as their organisation indicates,
essentially arboreal, and feed exclusively on fruit, leaves, buds, and
flowers. They are restricted geographically to the island of Madagascar.
Among them are the largest members of the suborder. A detailed and
beautifully illustrated account of their characters, external and
internal, and distribution and habits, is given in the _Histoire
Naturelle de Madagascar_, by A. Grandidier and Alphonse Milne-Edwards
(1875). The species are not numerous and are distributed into three
genera.
_Indris._[641]—Upper incisors subequal in size. Upper canine larger than
the first premolar. Muzzle moderately long. Ears exserted. Carpus without
an os centrale. Tail rudimentary. Vertebræ: C 7, D 12, L 9, S 4, C 9.
The only well-established species is the Indris (_I. brevicaudata_, Fig.
325), discovered by Sonnerat in 1780. It is the largest of the Lemurs,
the length of the head and body being about 2 feet, and the tail 2
inches. It is very variable in colour, for although usually nearly black,
marked with whitish spots principally in the lumbar region and forearm,
individuals have been found quite white. It inhabits exclusively the
forests of a part of the east coast of Madagascar, living in small troops
of four or five in number, and resembling in most of its habits the
animals of the next genus.
_Propithecus._[642]—Second upper incisor much smaller than the first.
Upper canine larger than the first premolar. Muzzle rather short. Ears
short, concealed by the fur. An os centrale in the carpus. Tail long.
Vertebræ: C 7, D 12, L 8, S 3, C 28.
[Illustration: FIG. 325.—Indris (_Indris brevicaudata_). From
Milne-Edwards and Grandidier, _Mammifères de Madagascar_, pl. 12.]
The species are all subject to great variations in colour, which has
led to much difficulty in discriminating them, and to much confusion of
synonymy. Grandidier and Milne-Edwards recognise three as certainly
distinct—_P. diadema_, _P. verreauxii_, and _P. coronatus_ (Fig. 326).
Some of these are to be found in almost every part of the island of
Madagascar, living in the woods in small bands of six or eight together,
and feeding exclusively on buds, flowers, and berries. Their powerful
hind limbs enable them to leap from tree to tree, often to a distance of
10 yards, without any apparent effort, and thus seeming to fly through
the air. When obliged to descend to the ground to pass from one clump
of trees to another they do not run on all fours, but stand erect, and
throwing their arms above their heads progress by a series of short
jumps, producing an effect which is described by travellers who have
seen them thus in their native haunts as exceedingly ludicrous. They are
not nocturnal, but most active in the morning and evening, remaining
seated or coiled up among the branches during the heat of the day. They
are naturally of a quiet and gentle disposition, and do not show much
intelligence. All the species are also less vociferous than the true
Lemurs, only when alarmed or angered making a noise which has been
compared to the clucking of a fowl. Like the rest of the subfamily they
never have more than a single young one at a time.
[Illustration: FIG. 326.—_Propithecus coronatus._ (From Milne-Edwards and
Grandidier, _Mammifères de Madagascar_, pl. 7.)]
_Avahis._[643]—Second upper incisor larger than the first. Upper canine
scarcely larger than the first premolar. Muzzle very short. Ears very
small and hidden in the fur, which is very soft and woolly. Carpus
without an os centrale. Tail long. Vertebræ: C 7, D 11, L 9, S 3, C 23.
One species, _A. laniger_, the Woolly Lemur, or Avahis, considerably
smaller than any of the last genus. It differs from them in its habits,
being quite nocturnal, and not associating in small troops, but being
always met with either alone or in pairs. It is very slow in its
movements, and rarely descends to the ground, but when it does it walks
upright like the other _Indrisinæ_. It is found throughout the forests
which clothe the mountains on the east coast of Madagascar, and also in a
limited district on the north-west coast, the specimens from the latter
locality being of smaller size and rather different in colour.
Subfamily =Lemurinæ=.—The dentition in the adult consists of thirty-six
teeth, which, as usually enumerated, are _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_
³⁄₃. In the fore part of the lower jaw are on each side three elongated,
compressed, procumbent teeth, of which the outer, usually considered
the homologue of the canine, is larger than the others. All the forms
have long tails. Hind limbs not of the same disproportionate size as in
the last group; and the cæcum much less developed. Tarsus but slightly
elongated, the calcaneum being always less than one-fourth the length of
the tibia. Toes of the hind feet free to the base. Habitat, Madagascar,
and some of the adjacent Comoro Islands.
[Illustration: FIG. 327.—Skull of Ring-tailed Lemur (_Lemur catta_). × ⅓;
_uc_, Upper canine; _lc_, lower canine; _pm_, premolars; _m_, molars.]
This group contains the typical Lemurs, or rather those to which the
term is now chiefly restricted. Two somewhat aberrant members make it
necessary to divide it into three genera.
_Lemur._[644]—Upper incisors separated by an interval in the middle, and
not in contact with each other or the canine, in front of which they are
both placed. Muzzle elongated. Ears conspicuous and tufted. Mammæ two,
pectoral. Vertebræ: C 7, D 12, L 7 (or D 13, L 6), S 3, C 27.
[Illustration: FIG. 328.—The Ring-tailed Lemur (_Lemur catta_).]
Animals much about the size of a common Cat, with Fox-like faces, soft
thick fur, and long tails well clothed with hair. Not having the same
disproportionate size of the limbs as the last group, they are much
more quadrupedal in their actions, walking on the ground or running
along the branches of trees on all four feet, but also jumping with
marvellous agility. They are gregarious, living in small troops, are
diurnal in their habits, but most active towards evening, when they make
the woods resound with their loud cries. They feed not only on fruits
and buds, but also on eggs, young birds, and insects. When at rest or
sleeping they generally coil their long, bushy tails around their bodies,
apparently for the sake of the warmth it affords. They have either one
or two young ones at a birth, which are at first nearly naked, and are
carried about, hanging close to and almost concealed by the hair of the
mother’s belly. After a while they change their position and mount upon
the mother’s back, where they are carried about until they are able to
climb and leap by themselves. Though no member of the _Indrisinæ_ has as
yet lived long enough in captivity to be brought alive to Europe, various
species of _Lemurinæ_ are commonly seen in menageries, and often breed in
England. They present a great tendency to variation in their colouring,
in consequence of which many nominal species have been made. The most
distinct, and at the same time most beautiful, is the Ring-tailed Lemur
(_L. catta_, Fig. 328), of a delicate gray colour, and with a long tail
marked with alternating rings of black and white. This is said by Mr.
G. A. Shaw[645] to be an exception to all the other Lemurs in not being
arboreal, but living chiefly among rocks and bushes. Pollen, however,
says that it inhabits the forests of the south-west parts of Madagascar,
living, like its congeners, in considerable troops, and not differing
from them in its habits. He adds that it is extremely gentle, and active
and graceful in its movements, and utters at intervals a little plaintive
cry like that of a domestic cat. All the others have the tail of uniform
colour. The largest species is _L. varius_, the Ruffed Lemur, sometimes
black and white, and sometimes reddish-brown, the variation apparently
not depending on sex or age, but on the individual. In _L. macaco_ the
male is black and the female red. _L. mongoz_, _L. collaris_, and _L.
albifrons_ are other well-known species.
_Hapalemur._[646]—Upper incisors very small, subequal, separated widely
in the middle line. Those of either side in contact with each other and
with the canine, the posterior one being placed on the inside, and not in
front of the latter. Muzzle very short and truncated. Mammæ four. There
is apparently but one species, _H. griseus_, smaller than any of the true
Lemurs, of a dark gray colour, with round face and short ears. It is
quite nocturnal, and lives chiefly among bamboos, subsisting on the young
shoots. A second species has been named _H. simus_, but it is doubtful if
it is more than a variety.
_Lepidolemur._[647]—Upper incisors absent or rudimentary. Muzzle more
elongated than in the last. No distinct os centrale in the carpus.
_L. mustelinus_ is the best-known species. It has, at all events when
adult, no upper incisors. It is rare, and like _Hapalemur_ nocturnal in
its habits. A second closely allied species, but with better developed
premaxillæ, containing a pair of small styliform incisors, has been
described by Peters[648] under the name of _Myxocebus caniceps_.
Subfamily =Galaginæ=.—Dentition as in _Lemurinæ_, from which the members
of this subfamily are distinguished by the elongation of the tarsus,
caused by a peculiar modification of the calcaneum and the navicular, the
distal portion of the former and the whole of the latter having the form
of almost cylindrical rods placed side by side, while the other bones
retain nearly their normal form and proportion.
_Chirogaleus._[649]—Last upper premolar very much smaller than the first
molar, with only one external cusp. The animals included under this name
appear to form a transition between the true Lemurs and the Galagos. The
genus was originally established by Geoffroy St. Hilaire in 1812 for
the reception of three species only known at that time by drawings made
in Madagascar by the traveller Commerson. Subsequent discoveries have
brought to light several others that may be referred to it, including
one or two which are sometimes considered as forming a genus apart under
the name of _Microcebus_. They are all small, some being less than a
rat in size, long-tailed, and nocturnal in their habits. One of the
largest, _C. furcifer_, is of a reddish-gray colour, and distinguished
by a dark median stripe on its back which divides on the top of the head
into two branches, one of which passes forwards above each eye. The most
interesting peculiarity of these animals, a knowledge of which we owe
to M. Grandidier, is that certain species (_C. samati_, _C. gliroides_,
_C. milii_, etc.) during the dry season coil themselves up in holes of
trees and pass into a state of torpidity like that of the hibernating
animals in the winter of northern climates. Before this takes place
an immense deposit of fat accumulates upon certain parts of the body,
especially upon the basal portion of the tail, which has then dimensions
corresponding to that of the well-known fat-tailed Sheep of the Cape, but
which by the time they emerge from their torpor has acquired its normal
proportions. The smallest species, to which many names have been given
(_C. pusillus_, _rufus_, _smithi_, etc.), lives among the small branches
on the tops of the highest trees, feeding on fruit and insects, and
making nests which resemble those of birds.
_Galago._[650]—Last upper premolar with two large external cusps, and
nearly equalling the first molar in size. Calcaneum about one-third the
length of the tibia, and the navicular much longer than the cuboid.
Vertebræ: C 7, D 13, L 6, S 3, C 22-26. Tail long, and generally bushy.
Ears large, rounded, naked, and capable of being folded at the will of
the animal. Mammæ four, two pectoral and two inguinal.
The Galagos differ from all the Lemuroids previously mentioned, inasmuch
as they are inhabitants, not of Madagascar, but of the African continent,
being widely distributed in the wooded districts from Senegambia in the
west to Abyssinia in the east, and as far south as Natal. They pass the
day in sleep, but are very active at night, feeding on fruit, insects,
and small birds. When they descend to the ground they sit upright, and
move about by jumping with their hind legs, like jerboas and kangaroos.
They are pretty little animals, varying in size from that of a small cat
to less than a rat, with large eyes and ears, soft woolly fur, and long
tails. There are several species, of which _G. crassicaudatus_, from
Mozambique, is the largest. A similar species, or perhaps variety, from
Angola is _G. montieri_. _G. garnetti_, _alleni_, _maholi_, _demidoffi_,
and _senegalensis_ are other recognised species. The last-mentioned was
the first known to science, having been brought from Senegal by Adanson,
and described in 1796 by Geoffroy, who adopted the name _Galago_, by
which it was said to be called by the natives.
Subfamily =Lorisinæ=.—Dental formula as in _Lemurinæ_. Index finger very
short, sometimes rudimentary and nailless. Fore and hind limbs nearly
equal in length. Tarsus not specially elongated. Pollex and hallux
diverging widely from the other digits, the hallux especially being
habitually directed backwards. Tail short or quite rudimentary. Mammæ
two, pectoral.
A small group of very peculiar animals, of essentially nocturnal habits,
and remarkable for the slowness of their movements. They are completely
arboreal, their limbs being formed only for climbing and clinging to
branches, not for jumping or running. They have rounded heads, very
large eyes, short ears, and thick, short, soft fur. They feed not only
on vegetable substances, but, like many of the _Lemuridæ_, on insects,
eggs, and also birds, which they steal upon while roosting at night. None
of the species are found in Madagascar. One of the greatest anatomical
peculiarities of these animals is the breaking up of the large arterial
trunks of the limbs into numerous small parallel branches, constituting a
_rete mirabile_, which is found also in the Sloths, with which the Loris
are sometimes confounded on account of the slowness of their movements.
The animals of this group are usually divided into four genera, though
the characters by which they are separated are very trivial. There are
more properly two natural divisions.
_A._ Characterised by the index finger being small, but having the
complete number of phalanges, and by their Asiatic habitat.
These form the genus _Loris_ of Geoffroy St. Hilaire (1796), _Stenops_
of Illiger (1811), but they were in 1812 divided by Geoffroy into two
genera, _Nycticebus_ and _Loris_, a division which has been accepted by
most modern zoologists.
_Nycticebus._[651]—First upper incisor larger than the second, which is
often early deciduous. Inner margins of the orbits separated from each
other by a narrow flat space. Nasal and premaxillary bones projecting
but very slightly in front of the maxillæ. Body and limbs stout. No
external tail. Vertebræ: C 7, D 17, L 6, S 3, C 12. The species are _N.
tardigradus_, the common Slow Lemur or Loris, of the Malay Countries,
Sumatra, and Borneo; _N. javanicus_, of Java; and _N. cinereus_ (Fig.
329) of Siam and Cochin China. The habits of all are much alike. They
lead a solitary life in the recesses of large forests, chiefly in
mountainous districts, where they sleep during the day in holes or
fissures of large trees, rolled up into a ball, with the head between the
hind legs. On the approach of evening they awake; and during the night
they ramble among the branches of trees, slowly and quietly, in search
of their food, which consists of tender leaves and fruit, small birds,
insects, and mice. When in quest of living prey they move noiselessly
till quite close, and then suddenly seize it with one of their hands. The
female produces but one young one at a time. _L. tardigradus_ was placed
by Linnæus at the head of the list of species of his genus _Lemur_, and
its habits doubtless suggested the generic name which was transferred by
Geoffroy to the less nocturnal and spectre-like Madagascar members of the
group.[652]
[Illustration: FIG. 329.—The Gray Loris (_Nycticebus cinereus_). From A.
Milne-Edwards, _N. Archives du Muséum_, vol iii. pl 3.]
_Loris_.[653]—Upper incisors very small and equal. Orbits very large,
and only separated in the middle line above by a thin vertical plate of
bone. Nasals and premaxillæ produced forwards considerably beyond the
anterior limits of the maxillæ, and supporting a pointed nose. Body and
limbs slender. No external tail. Vertebræ: C 7, D 14, L 9, S 3, C 6.
This genus is represented only by the Slender Loris (_L. gracilis_) of
Southern India and Ceylon (Fig. 330). This species is common in some
of the forest regions of Southern India, and may be purchased in the
bazaars at Madras, its eyes being regarded as a remedy by the natives for
ophthalmic diseases. It is a strange-looking creature, about the size
of a squirrel, of a yellowish-brown colour, with large, prominent eyes,
pointed nose, long thin body, long, angularly bent, slender limbs, and no
tail. Its habits, according to Mr. W. T. Blanford,[654] are “very similar
to those of _Nycticebus tardigradus_, except that the Slender Loris is
rather quicker in its movements, though still slow in general. Like its
ally, it is purely nocturnal and arboreal, living upon shoots and young
leaves, insects, birds’ eggs, birds, and lizards. It is said to be very
fond of honey or syrup. It sleeps rolled up in a ball with its head
between its legs, grasping its perch with its arms.”
[Illustration: FIG. 330.—The Slender Loris (_Loris gracilis_). From
Blanford, _Mammalia of British India_, p. 47.]
_B._ Index fingers reduced to a mere tubercle without nail. Both the
known species are from West Africa.
_Perodicticus._[655]—A short tail, about a third of the length of the
trunk. Two or three of the anterior dorsal vertebræ have very long
slender spinous processes which in the living animal project beyond the
general level of the skin, forming distinct conical prominences, covered
only by an exceedingly thin and naked integument. The Potto, _P. potto_,
is one of the oldest known members of the lemuroid group, having been
described in 1705 by Bosman, who met with it in his voyage to Guinea.
It was, however, lost sight of until 1825, when it was rediscovered in
Sierra Leone, and fully described by Bennett in 1830 under the name of
_Perodicticus geoffroyi_. Bennett’s generic name has been retained, but
the specific name bestowed by Gmelin, adopted from Bosman, has been
restored. It is also found in the Gaboon. It is strictly nocturnal,
and slower in its movements even than _Nycticebus tardigradus_, which
otherwise it much resembles in its habits.
A second species, the Awantibo (_P. calabarensis_), rather smaller and
more delicately made, with smaller hands and feet and rudimentary tail,
constitutes the genus _Arctocebus_ of Gray. It is found at Old Calabar,
and is very rare, only a few individuals having as yet been met with.
Vertebræ: C 7, D 15, L 7, S 3, C 9.[656]
_Family_ TARSIIDÆ.
Dentition: _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total 34. The first upper
incisor large, and in contact with its fellow of the opposite side.
Canine of moderate size. Molars with numerous pointed cusps. Lower canine
semi-erect, its apex diverging from that of the single incisor. First
lower premolar smaller than those behind it. Orbit to a large extent
separated from the temporal fossa by a bony partition. Fibula slender,
with its lower half confluent with the tibia. Second and third digits of
the hind foot with compressed claws; all the other digits of both feet
with flat nails. Calcaneum and navicular bone of the foot elongated as in
the Chirogales and Galagos, but to a still greater extent. Colon short
and not folded. Vertebræ: C 7, D 13, L 6, S 3, C 27.
_Tarsius._[657]—The family contains the single genus _Tarsius_, of which
but one species is known, _T. spectrum_, the Tarsier, a very singular
little animal, rather smaller than an English squirrel, with very large
eyes and ears, a long thin tail, tufted at the end, and immensely
elongated tarsal portion of the foot, in allusion to which its generic
name was given to it. It inhabits the forests of many of the islands of
the Indo-Malayan archipelago, including Sumatra, Borneo, Celebes, and
some of the Philippines, feeds chiefly on insects and lizards, sleeps
during the day, but is tolerably active at night, moving chiefly by
jumping from place to place, an action for which the structure of its
hind legs, which present a curious resemblance to those of a frog, seems
particularly well adapted. It is rare, not more than two being generally
found together, and only brings forth one young at a time.[658]
_Family_ CHIROMYIDÆ.
Dentition of adult: _i_ ¹⁄₁, _c_ ⁰⁄₀, _p_ ¹⁄₀, _m_ ³⁄₃; total 18.
Incisors very large, compressed, curved, with persistent pulps and enamel
only in front, as in Rodents. Teeth of cheek series with flat, very
indistinctly tuberculated crowns. In the young the first set of teeth
more resemble those of the normal lemurs, being _i_ ²⁄₂, _c_ ¹⁄₀, _m_
²⁄₂, all very small. Orbit surrounded by a ring of bone posteriorly,
beneath which it communicates freely with the temporal fossa. Fibula well
developed and distinct from the tibia. All the digits of both feet with
pointed rather compressed claws, except the hallux, which has a flattened
nail. Middle digit of the hand excessively attenuated. Vertebræ: C 7, D
12, L 6, S 3, C 27.
[Illustration: FIG. 331.—Skull of Aye-aye (_Chiromys madagascariensis_).
× ⅙ Mus. Roy. Coll. Surgeons.]
_Chiromys._[659]—This family, like the last, is formed for the
reception of a single genus, _Chiromys_,[660] containing one species,
_C. madagascariensis_, the Aye-aye, an animal about the size of a cat,
with a broad rounded head, short face, and large and naked ears. It has
very large hands and long thin fingers with pointed claws, one of which
(the middle or third) is remarkable for its extreme slenderness. The
foot resembles that of the other lemurs in its large opposable hallux,
with a flat nail, but all the other toes have pointed compressed claws,
like that of the second toe in the _Lemurinæ_ and the second and third
in the _Tarsiidæ_. Tail long and bushy. General colour dark brown, the
outer fur being long and rather loose, with a woolly undercoat. Mammæ
two, inguinal in position. It is a native of Madagascar, where it was
discovered by Sonnerat in 1780. The specimen brought to Paris by that
traveller was the only one known until 1860. Since then many others have
been obtained, and they may frequently be seen living in the gardens of
the Zoological Society of London. Like so many of the Lemurs, the Aye-aye
is completely nocturnal in its habits, living either alone or in pairs,
chiefly in the bamboo forests. Observations upon captive specimens have
led to the conclusion that it feeds principally on succulent juices,
especially of the sugar-cane, which it obtains by tearing open the hard
woody circumference of the stalk with its strong incisor teeth. It is
said also to devour certain species of wood-boring caterpillars, which
it obtains by first cutting down with its teeth upon their burrows, and
then picking them out of their retreat with the claw of its attenuated
middle finger. It constructs large ball-like nests of dried leaves,
lodged in a fork of the branches of a tree with the opening on one side.
The resemblance of its teeth to those so characteristic of the Rodentia
caused it to be placed formerly in that order, and it was only when its
anatomical characters were fully known that its true affinities with the
Lemurs became apparent.[661]
_Extinct_ LEMUROIDS.
The discoveries of the last few years have revealed the former existence,
both in Europe and North America, of a number of extinct animals more
or less closely allied to the living Lemurs, which are of especial
interest as showing in some instances characters of a more generalised
type than is the case with the living representatives of the suborder.
It is, however, in some cases very difficult to determine whether these
extinct forms should be referred to the Lemuroidea or Insectivora; and
if those naturalists are right who regard these groups as survivors of a
very generalised ancestral type of mammalian organisation, it is to be
expected that as we recede in time we should find that the two groups
show more and more marked signs of a natural connection. The earliest
reference of one of these extinct Upper Eocene types to the Primates was
made in 1862 by Professor L. Rütimeyer, of Basle, who described part of
an upper jaw with three teeth from the so-called Bohnerz of Egerkingen,
near Soleure in Switzerland, under the name of _Cænopithecus lemuroides_,
regarding the animal to which the specimen belonged as partaking of
the characters both of the Lemurs and the American Monkeys. Most other
palæontologists refused, however, to accept this determination, and it
was not until many years later that the researches of Gaudry and Filhol
showed not only that _Cænopithecus_ was indeed a true Lemuroid, but also
that it was either identical with or closely allied to a form described
by Cuvier in the early part of this century under the name of _Adapis_
and regarded as referable to the Ungulata. Later researches have brought
to light other Lemuroids in the Tertiaries of both the Old and the New
World; and it is very noteworthy that all these types seem to have
disappeared from both regions with the close of the upper portion of the
Eocene period.
[Illustration: FIG. 332.—The last five right upper cheek-teeth of
_Microchœrus antiquus_ (_A_) and _Microchœrus erinaceus_ (_B_). Twice
natural size, and natural size.]
Among the more interesting of the forms which are generally regarded
as true Lemuroids we may first mention a small species from the Quercy
Phosphorites, of which the hinder cheek-teeth are shown in Fig. 332,
_A_, which was originally described as _Necrolemur antiquus_, but
appears to be generically identical with _Microchœrus erinaceus_, of the
upper Eocene of Hampshire, of which the corresponding teeth are shown
in _B_ of the same figure. In this genus, according to Dr. Schlosser,
the dental formula is _i_ ²⁄₁, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃, or the same
as in the existing _Tarsius_; but it is not improbable that in some
instances the first lower premolar may have been developed. The upper
molars of _M. erinaceus_ differ from those of _M. antiquus_ by the
simpler structure of their columns and the smaller size of the external
cingulum, which lacks the median cusp found in the latter. The angle of
the mandible is produced into a large hook-like flange which at once
distinguishes the genus from all existing Lemurs; and the anterior lower
premolar is not canine-like. _M. antiquus_ is of very small size, but
the larger _M. edwardsi_ of the same deposits comes nearer in dimensions
to _M. erinaceus_. The upper molars decrease in size from the first to
the third, the first and second having a median cusp in the external
cingulum, by which they are readily distinguished from the corresponding
teeth of the under-mentioned genus _Hyopsodus_. The third upper molar
differs from that of _Hyopsodus_ by its small size and the abortion of
its posterior columns. The skull approximates to that of the living genus
_Galago_, exhibiting the same inflation of the auditory bulla. The upper
molars are also not unlike one species of that genus, but the fourth
upper premolar has but one outer cusp, as in _Chirogaleus_.
The small _Anaptomorphus_, from the North American Eocene, has a skull of
about the same size as that of the smallest species of _Microchœrus_, but
the dental formula is _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃, and the upper
molars are of the tritubercular type.
[Illustration: FIG. 333.—The left upper cheek-teeth of _Adapis magna_,
from the Upper Eocene of Hampshire.]
The well-known _Adapis_ (_Aphelotherium_ or _Palæolemur_), of the Upper
Eocene of France and England, differs from all existing Lemuroids in
possessing four premolars[662]; the dental formula being _i_ ²⁄₂, _c_
¹⁄₁, _p_ ⁴⁄₄, _m_ ³⁄₃. The fourth upper premolar has two outer cusps,
and the upper molars (Fig. 333) resemble those of _Lepidolemur_ and
_Hapalemur_, while the lower canine is a well-developed tooth performing
the usual function of biting against the canine of the upper jaw. The
lower incisors have upright, spatulate crowns, as in the true Apes. The
skull is said to approximate in contour to that of _Propithecus_. The
typical _A. parisiensis_ is of comparatively small size, but the species
of which the upper cheek-teeth are shown in the woodcut is of much larger
dimensions. The skull of _A. magna_, which measures upwards of 4 inches
in length, resembles that of _A. parisiensis_ in its general characters,
but is modified much in the way that the skulls of larger animals differ
from the smaller ones of the same natural group. Thus the brain-chamber
and orbits are relatively smaller, the face larger, the muscular crests
more developed, and the constriction between the cerebral and the facial
portion of the skull more marked. These modifications remove the skull
in its general characters still farther from the existing Lemurs—so
much so that M. Filhol refers it and the other species of _Adapis_ to
a distinct zoological type, intermediate between the lemurs and the
pachyderms, to which he gives the name of _Pachylemuriens_, but later
researches do not support this view. As mentioned above, it has been
suggested that _Cænopithecus lemuroides_ is inseparable from _Adapis
parisiensis_, but the postero-internal column of the upper molars is said
to be larger. The genera _Tomitherium_ and _Notharctus_, of the Eocene
of the United States, appear to be allied to _Adapis_, but the second
has a larger lower canine. The same deposits have also yielded more or
less imperfect remains of other forms departing more widely from the
existing Lemuroid type. Of these _Hyopsodus_, of the Wasatch and Bridger
Eocene of the United States, has the dental formula _i_ ²⁄₂, _c_ ¹⁄₁,
_p_ ⁴⁄₄, _m_ ³⁄₅. The quadrituberculate upper molars have well-developed
accessory intermediate columns (protoconule and metaconule), and thus
resemble those of _Microchœrus_; the external surfaces of the outer
columns of their teeth being flattened, with vertical ridges and a
distinct cingulum. The third upper molar has its postero-internal column
(hypocone) partly aborted, but is otherwise as well developed as the
preceding molars. _Microsyops_, of the North American Eocene, appears
to have been an allied form in which there were probably only three
premolars.
[Illustration: FIG. 334.—The right upper cheek-teeth of _Plesiadapis
remensis_; from the Lowest Eocene of Rheims. × ³⁄₂. _p_, 3, 4, premolars;
_m_, 1, 2, 3, molars. (From Osborn.)]
The genera _Protoadapis_ and _Plesiadapis_, from the lowest Eocene of
Rheims, may not improbably be regarded as primitive Lemuroids. The lower
molars are quinquetubercular, and not unlike those of _Microsyops_; the
dental formula of the lower jaw is _i_ 2, _c_ 1, _p_ 3-4, _m_ 3 in the
first-named genus, but in the second the dentition is reduced to _i_
²⁄₁, _c_ ¹⁄₀, _p_ ²⁄₂, _m_ ³⁄₃. In _Plesiadapis_ the lower and the first
upper incisor are enlarged, the upper molars (Fig. 334) tritubercular,
and the lower quadritubercular. _Indrodon_, of the lowest Eocene of the
United States, resembles _Plesiadapis_ in its tritubercular upper molars,
and appears to have a nearly similar dental formula. _Mixodectes_, of
the same deposits, was probably a more or less closely allied type.
_Pelycodus_ of the Wasatch Eocene of North America, in which the hallux
was not opposable, and _Cryptopithecus_ of the German Eocene, may be
regarded as very generalised Lemuroids.
_Bibliography._—Besides the works and memoirs on particular
families and genera referred to above, see St. G. Mivart,
“Notes on the Crania and Dentition of the _Lemuridæ_,” in
_Proc. Zool. Soc._ 1864 (pp. 611-648) and 1867 (pp. 960-975);
Mivart and Murie, “On the Anatomy of the _Lemuroidea_,” in
_Trans. Zool. Soc._ 1872, vol. vii. pp. 1-113; W. Turner, “On
the Placentation of the Lemurs,” in _Phil. Trans._ vol. clxvi.
pp. 569-587; F. Pollen and D. C. Van Dam, _Recherches sur la
Faune de Madagascar_. 2ᵐᵉ parte, “Mammifères,” 1868. For the
fossil types see M. Schlosser, “Die Affen, Lemuren, etc., des
Europäischen Tertiärs,” in _Beitr. Pal. Œstr-Ungar_, 1888.
_Suborder_ ANTHROPOIDEA.
This suborder includes the whole of the remaining members of the
Primates, namely, those animals commonly known as Marmosets, Monkeys,
Baboons, and Apes, together with Man himself. The characters by which
the Anthropoidea are distinguished as a whole from the Lemuroidea may be
summarised as follows. Skull with the orbit separated from the temporal
fossa by a vertical plate of bone joining the postorbital bar, and
the lachrymal foramen situated within the margin of the orbit. Pollex
sometimes rudimentary or absent; second digit of manus always well
developed, and that of the pes usually with a flattened nail (not so in
_Hapalidæ_). The cerebral hemispheres of the brain either completely
or almost completely cover the cerebellum, and are much convoluted.
Uterus not bicornuate. The placenta is deciduate and discoidal; and the
allantois is small. There are never abdominal mammæ. As additional points
of distinction from the Lemuroidea, it may be mentioned that the anterior
cornu of the hyoid is shorter than the posterior; the inner pair of upper
incisors are in contact in the middle line; and the transverse portion of
the colon extends uninterruptedly across the abdomen.
The Anthropoidea may be divided into the five families—_Hapalidæ_,
_Cebidæ_, _Cercopithecidæ_, _Simiidæ_, and _Hominidæ_, of which the first
and second are confined to the New, and the third and fourth to the Old
World.
In noticing some of the salient features in the external and internal
structure of the Anthropoidea it will be found convenient to allude to
all the members of the first four families as Apes, in contradistinction
to Man. In respect to relative size the extremes are found in the Gorilla
on the one hand and _Hapale_ on the other; the difference in this
respect between these two forms being greater than that between Man and
a Squirrel. The relative proportions between the limbs and the body, and
also between the fore and hind limbs, are subject to great variation.
Thus in _Hylobates_ and _Ateles_ both pairs of limbs are much elongated;
in the former case the pectoral being much longer than the pelvic pair
(Fig. 335). In other cases, as in the Orang (Fig. 354), while the arms
are very long, the legs are short; but in the subfamily _Cercopithecinæ_
both pairs are short and subequal. Only in the _Hapalidæ_ and some of the
_Cebidæ_ are the legs proportionately as long as in Man.
The tail is as much as three times the length of the body in _Ateles_;
while in the _Simiidæ_ it is totally absent. In the majority of genera it
is long in all the species; but in some cases, as in _Macacus_, it may be
either long, short, or absent in the different species of a single genus.
Equally marked variations occur in the shape of the head. Thus in
_Ateles_ it is rounded; while in the Orang it is elevated vertically;
in _Chrysothrix_ it is produced posteriorly; and in the Baboons
(_Cynocephalus_) it is characterised by the great production of
the muzzle and the terminal position of the nostrils, whereby a
characteristic Dog-like form is assumed. The eyes are always directed
forwards, and are never more separated from one another than in Man,
although, as in _Chrysothrix_, they may be closer together. They are
of very large size in _Nyctipithecus_, while in the Baboons they are
relatively small in proportion to the size of the head. The ears
are invariably well developed, and are usually pointed at their
postero-superior angle. Those of man are characterised by the soft
depending portion known as the “lobule,” of which there is a rudiment
in the Gorilla. In the majority of Apes the nose is but very slightly
prominent; but it attains an extraordinary development in _Nasalis
larvatus_, and is scarcely less remarkable in _Semnopithecus roxellanæ_
(Fig. 349). Among the Gibbons the Hoolock has a distinctly aquiline nose.
The nostrils are terminal in the true Baboons; and while in all the Old
World Apes they are approximated, in those of the New World they are
separated by a broad septum. With the exception of the Orang, the lips of
the Apes are thin.
The pollex makes a nearer approach in form to the human thumb in the
Chimpanzee than in any other Ape. Man differs from all the Apes in having
the hallux frequently longer instead of shorter than the other digits of
the foot. The hallux of the Orang is peculiar in having no nail, but in
other cases the nail is flat; the nails of the other digits of the Apes
are never quite flat, and in some of the _Cebidæ_ they are decidedly
compressed laterally, while in the _Hapalidæ_ they assume the form of
sharp and curved claws.
All the Apes have the greater part of the body well clothed with hair. In
the Gibbons and the _Cercopithecidæ_ the buttocks have naked ischiatic
callosities, which attain their greatest development in _Cynocephalus_
and its allies. The male of the Orang has a well-developed beard, and in
_Cercopithecus diana_ there is long hair on the cheeks and chin, while
in _Macacus silenus_ the face is surrounded by a fringe of long hair,
separated by an interval on the forehead. Long hair is found on the
head in _Hapale œdipus_ and in some species of _Semnopithecus_; while
in the Bonnet Monkey (_Macacus sinicus_) it radiates in all directions
from a central point on the vertex. Long hair clothes the shoulders
in _Cynocephalus hamadryas_ and _Hapale humeralifer_; and the end of
the tail has a tuft in two species of _Cynocephalus_ and in _Macacus
sinicus_. Many of the African _Colobi_ and some species of the Howlers
have very long hair on the flanks; and in _Pithecia_ this development of
hair extends to the greater part of the body and the tail, _P. satanas_
also having a long beard. In all the lower Apes the hairs on the arm and
forearm are directed towards the hand quite down to the wrist; and the
same arrangement obtains in _Hylobates_. In the other _Simiidæ_, however
(as in man), the points of the hairs of the arm and forearm converge
at the elbow. Darwin’s explanation of this peculiarity is that these
Apes are accustomed to sit with the arms bent, so that the rain is thus
enabled to run off at the elbow.
In one species of _Hapale_ the hair is of a silky texture, and in the
South American _Eriodes_, and _Macacus tibetanus_ (as in all the mammals
inhabiting the arid and severe climate of Tibet) it becomes woolly.
The development of very brilliant colours on the naked parts of the body,
such as the face, sexual organs, and ischiatic callosities is a marked
feature of many of the _Cercopithecidæ_ and some other Apes.
With the exception of the long tail found in most forms, the general
structure of the skeleton of the Apes is very similar to that of man,
but there are marked differences in the form of the jaws and of the
innominate bones. The proportion of the facial to the cranial region
of the skull varies with the shape of the head, of which brief mention
has already been made; the greatest development of the facial portion
being in the Baboons. Curiously enough, some of the lower American
Monkeys, and more especially _Chrysothrix_, have the greatest relative
development of the cranial part of the skull of all the Apes; this
character being, however, one common to all the smaller representatives
of particular groups, and obviously necessary to provide the requisite
amount of brain-space. In the convexity of the frontal region of the
skull the American forms, and more especially _Pithecia_, make the
nearest approximation to man, and the same is true with regard to the
occipital production, which is most developed in _Chrysothrix_. Most of
the _Simiidæ_ exhibit, however, a distinct convexity of the occiput,
and thereby differ markedly from the _Cercopithecidæ_, in which this
region is flat. The rotundity of the cranium is obscured in the larger
Apes, such as the Orang (Fig. 353) and Gorilla, by the development of
prominent bony ridges for muscular attachment; these attaining their
maximum in the males of the species last named, where the sagittal crests
and the supraorbital ridges are very prominent. The mastoid process is
always smaller in the Apes than in Man, and as it diminishes in size the
petrosal tends to assume an inflated or bullate condition. The orbits in
shape are most like that of Man in the Gorilla; and, in accordance with
the size of the eyes, they are of enormous dimensions in _Nyctipithecus_.
The angle formed by the plane of the foramen magnum with that of the
basicranial axis is subject to variation according to the degree of
convexity of the occiput, but is generally smaller than in Man, although
larger in _Chrysothrix_. There is an external bony meatus auditorius in
Man, the _Simiidæ_, and the _Cercopithecidæ_, but none in the _Cebidæ_
and _Hapalidæ_.
The premaxillæ of the Apes are always large; and, except in the
Chimpanzee, the premaxillo-maxillary suture persists until after the
permanent dentition has been developed. The nasals are smaller and
flatter than in Man, but are largest in _Mycetes_. The two rami of the
mandible are invariably completely ankylosed at the symphysis in the
adult. The Siamang (_Hylobates syndactylus_) is the only ape in which the
mandibular symphysis slows a slight projection in front corresponding
to the human chin. In _Mycetes_ the angle of the mandible attains an
enormous development (Fig. 338) to protect the huge inflated basihyal.
The frontal sinuses, though present, in the _Simiidæ_, are generally
replaced in the _Cercopithecidæ_ by a coarse diploë, but they are present
in the _Cebidæ_ and _Hapalidæ_, being especially large in _Cebus_. In
fully adult individuals the cranial sutures become obliterated, the
internasal suture disappearing at an early age in the _Simiidæ_ and most
of the _Cercopithecidæ_. As in many Carnivora, the tentorium, or membrane
separating the cerebrum from the cerebellum, may become ossified in some
of the American forms.
The number of the teeth in the Old World Apes is invariably the same as
in Man, namely _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ³⁄₃, total 32; but in the
_Cebidæ_ the cheek-teeth are _p_ ³⁄₃, _m_ ³⁄₃, and in the _Hapalidæ_ _p_
³⁄₃, _m_ ²⁄₂. It is probable that the two pairs of incisors correspond
to the first and third of the typical series of three. In all Apes the
dental series is interrupted by a diastema, and the canines of the
males are large. Man alone has an uninterrupted dental series of a
horse-shoe-form, without prominent canines.
According to recent researches the Chimpanzee and some of the other
_Simiidæ_ exhibit a more or less close approximation to the sigmoid
curvature of the vertebral column which is so characteristic of Man,
and there is also some approach to it in the Baboons. The number of
dorsal vertebræ in the Apes may vary from eleven, as in some species
of _Cercopithecus_ and _Macacus_, to fourteen in certain forms of
_Hylobates_, and to fifteen in _Nyctipithecus_. The _Cebidæ_ generally
have thirteen; and the same number obtains in the Chimpanzee and Gorilla,
while the Orang resembles Man in having but twelve. The lumbar vertebræ
show a range in number of from four to seven. In the _Simiidæ_ there are
four or five of these vertebræ, the length of the lumbar region being
shorter in this family than in the other Apes, with the exception of
_Ateles_. The shortness of the lumbar region in the last-named genus is
compensated by the relative length of the dorsal region, as is shown in
Fig. 335.
[Illustration: FIG. 335.—Skeleton of the Black-handed Spider Monkey
(_Ateles geoffroyi_). From De Blainville.]
The sacrum is longest in the _Simiidæ_ and Man, its greatest absolute
length occurring in the Gorilla, and the relative greatest length being
found in _Hylobates_. The _Simiidæ_ never have less than five, and may
have six sacral vertebræ; while in the lower forms there are generally
only two or three, although occasionally four in some of the American
forms. The Orang and some of the Baboons make the nearest approximation
to Man in the marked angle formed at the junction of the sacrum with
the lumbar vertebræ. Except in the _Simiidæ_ and _Macacus inuus_, the
number of caudal vertebræ in the Apes always exceeds four, but they may
be reduced to five in the Mandrill (_Cynocephalus maimon_). In _Macacus_
and _Uacaria_ the shortness of the tail is attained by the small size
of the vertebræ themselves, the number of which may be from fifteen to
seventeen. Other forms usually have from twenty to thirty-three caudals,
the latter number occurring in _Ateles_ (Fig. 335), where the tail is
relatively the longest. The tail is, however, absolutely longest in
_Semnopithecus_, _Colobus_, and their allies, the length being partly
due to the size of the component vertebræ. Chevron bones are present in
all forms having a distinct tail; and, together with other processes for
muscular attachment, attain their greatest development in _Ateles_.
The vertebral processes known as metapophyses and anapophyses, which
are generally inconspicuous in Man, and are but small in the _Simiidæ_,
attain a large development in the lower forms. The metapophyses
generally commence in the eighth or ninth dorsal, and continue to the
anterior caudals, where they gradually merge in the prezygapophyses.
The anapophyses, which are most developed in the _Cebidæ_, project
outwards and backwards from one vertebra to embrace the prezygapophyses
of the succeeding one. They occur generally in the same region as the
metapophyses, but usually cease at the penultimate lumbar, although in
some cases they can be traced on to the posterior cervicals and anterior
caudals, in the latter region passing into the transverse processes.
In most Apes the sternum is narrow, and consists of a more or
less enlarged manubrium, followed by a chain of subequal and
antero-posteriorly elongated bones, from three to six in number. In
the _Simiidæ_ alone is there a broad sternum, or one consisting of a
manubrium, followed by a single bone only, as in _Hylobates_. The Orang
presents a peculiarity, in that the sternum long remains made up of
ossifications arranged in pairs, side by side, successively. The true
ribs are seven in number on each side in the highest forms, but in
_Hylobates_ there are sometimes eight. In _Ateles_ there are sometimes
nine pairs. In _Hapale_ the number varies from six to eight, and it is
seven or eight in the other genera. The angles of the ribs are never so
marked as in Man; although most marked in _Hylobates_. _Pithecia_ is
distinguished by the greater relative breadth of the ribs. In no Ape is
the thorax half as broad again as it is deep from back to breast; but in
the _Simiidæ_ its transverse diameter exceeds its depth by from about
one-fourth to a little under one-third of the latter. In _Ateles_, and
sometimes in _Mycetes_, the thorax is wider than deep, but in all the
rest it is deeper than wide.
In regard to the appendicular skeleton it may be observed that the
Gorilla and Orang make the nearest approach to Man in the form of the
scapula; and that the supraspinous fossa of this bone is largest in
_Gorilla_ and _Mycetes_, being remarkably small in _Simia_. The _Cebidæ_
have a distinct suprascapular notch which is often converted by a bar of
bone into a foramen; this bar in _Mycetes_ giving rise to a peculiar flat
process. The acromion and coracoid processes are most developed in the
_Simiidæ_ and _Ateles_.
The relative length of the fore and hind limbs has been already briefly
touched upon. The humerus closely resembles that of Man throughout the
suborder; the nearest approximation occurring in the _Simiidæ_. As in the
Lemuroidea, this bone never has an entepicondylar foramen, but in many
of the American forms it has a supracondylar perforation. The radius and
ulna, like the tibia and fibula, are always perfectly distinct throughout
their length; and the hand can be pronated and supinated upon the
forearm. Man, the Gorilla, and the Chimpanzee differ from other forms in
having no os centrale in the carpus.
The brain of Apes is always much smaller in absolute dimensions than in
Man. Thus, according to Professor Mivart,[663] “the cranial capacity is
never less than 55 cubic inches in any normal human subject, while in
the Orang and Chimpanzee it is but 26 and 27½ cubic inches respectively.
The relative size of the brain varies inversely with the size of the
whole body, but this is the case in warm-blooded vertebrates generally.
The extreme length of the cerebrum never exceeds, as it does in Man, two
and a quarter times the length of the basicranial axis. The proportion
borne by the brain to its nerves is less in the Apes than in Man, as also
is that borne by the cerebrum to the cerebellum. In general structure
and form the brain of Apes greatly resembles that of Man. Each half
of the cerebrum contains a triradiate lateral ventricle, and though
in some _Cercopithecidæ_ the posterior cornu is relatively shorter
than in man, it again becomes elongated in the _Cebidæ_, and in many
of the latter it is actually longer relatively than it is in man. The
posterior lobes of the cerebrum are almost always so much developed as
to cover over the cerebellum, the only exceptions being the strangely
different forms _Mycetes_ and _Hylobates syndactylus_. In the latter
the cerebellum is slightly uncovered, but it is so considerably in the
former. In _Chrysothrix_ the posterior lobes are much more largely
developed relatively than they are in man. The cerebrum has almost always
a convoluted external surface. In this group, however, as in mammals
generally, a much-convoluted cerebrum is correlated with a considerable
absolute bulk of body. Thus in _Hapale_ (and there only) we find the
cerebrum quite smooth, the only groove being that which represents the
Sylvian fissure. In _Simia_ and _Gorilla_ and _Anthropopithecus_, on the
contrary, it is very richly convoluted. A hippocampus minor is present
in all Apes, and in some of the _Cebidæ_ it is much larger relatively
than it is in Man, and is absolutely larger than the hippocampus major.
Of all Apes, the Orang has a brain which is most like that of Man;
indeed, it may be said to be like Man’s in all respects, save that it
is much inferior in size and weight, and that the cerebrum is more
symmetrically convoluted and less complicated with secondary and tertiary
convolutions. If the brain of _Simia_ be compared with that of _Gorilla_
and _Anthropopithecus_, we find the height of the cerebrum in front
greater in proportion in the former than in the latter; also the bridging
convolutions, though small, are still distinguishable, while they are
absent in the Chimpanzee. Nevertheless this character cannot be of much
importance, since it reappears in _Ateles_, while two kinds of the genus
_Cebus_ (so closely allied as to have been sometimes treated as one
species) differ strangely from each other in this respect. The corpus
callosum, in Apes generally, does not extend so far back as in Man, and
it is very short in _Pithecia_. In the Orang and Chimpanzee there are,
as in Man, two corpora albicantia, while in the lower Monkeys there is
but one. The vermis of the cerebellum is larger in the _Cebidæ_ than
in the _Simiidæ_ and _Cercopithecidæ_. In all Apes below the _Simiidæ_
each lateral lobe of the cerebellum gives off a small lobule, which is
received into a special fossa of the petrous bone. Certain prominences
of the medulla oblongata, termed corpora trapezoidea, which are found in
lower mammals, begin to make their appearance in the _Cebidæ_.”
The organs connected with the functions of alimentation, circulation,
and excretion, as well as the muscles, conform generally to the type
obtaining in Man, of which full description will be found in works on
human anatomy. The tongue is longer in Apes than in Man; and a uvula is
generally present, although rudimentary in the _Cebidæ_. The peculiar
sacculation of the stomach in the subfamily _Semnopithecinæ_ has been
already mentioned; this sacculation is most developed at the cardiac
extremity, where it somewhat resembles a colon spirally coiled. In
_Hylobates_ the stomach is very like that of Man, differing only in the
more elongated and distinct pylorus. _Pithecia_ has a more globular
stomach, while in _Hapale_ the cardiac and pyloric apertures are
approximated. The intestine of Apes is devoid of valvulæ conniventes,
and it is only in Man and the _Simiidæ_ that the colon is furnished with
a vermiform appendage. The colon varies from a fully sacculated form in
_Hylobates_ to a smooth one in _Cebus_.
The liver of Apes is subject to a considerable amount of variation. In
the _Simiidæ_ it comes more or less close to the human type; that of
the Orangs being usually divided only into two principal lobes by the
umbilical vein, and showing no trace of lateral fissures. In the Gorilla
these fissures are present, so as to produce right and left lateral
and central lobes. _Hylobates_ has a liver (Fig. 352) which perhaps
is nearer to the human than that of any of the other _Simiidæ_. In the
_Cercopithecidæ_ the liver differs from that of the _Simiidæ_ by the
deeply cleft lateral fissures, and has a comparatively small and pointed
caudate lobe. The enormous size of the stomach in _Colobus_ causes the
liver to be very narrow, and pushed to the left side. The liver of the
_Cebidæ_ (Fig. 336) and _Hapalidæ_, in addition to the deeply cleft
lateral fissures, is characterised by the great size and quadrangular
form of the caudate lobe (_c_), which attains its maximum development in
_Ateles_. The gall-bladder is always present.
[Illustration: FIG. 336.—Under surface of the liver of the Black-handed
Spider Monkey (_Ateles melanochir_). _u_, Umbilical fissure; _vc_, vena
cava; _ll_, left lateral lobe; _lc_, left central lobe; _rc_, right
central lobe; _rl_, right lateral lobe; _s_, Spigelian lobe; _c_, caudate
lobe; _g_, gall-bladder.]
The larynx is in many Apes furnished with sac-like appendages, which are
variable in different species as regards number, size, and situation.
They may be dilatations of the laryngeal ventricle, as in _Simia_,
_Gorilla_, and _Anthropopithecus_, or they may open above the false
vocal chords so as to be extensions of the thyro-hyoid membrane,
as in _Hylobates_. There may be but a single median opening in the
front part of that membrane at the base of the epiglottis, as in the
_Cercopithecidæ_. There may be a single median opening at the back of the
trachea, just below the cricoid cartage, as in _Ateles_; there may be but
a single sac, or there may be five, as sometimes in _Mycetes_. These may
be enormous, meeting in the middle line in front and extending down to
the axillæ, as in the Gorilla and Orang. A sac may occupy the cavity of
the expanded body of the hyoid, as in _Mycetes_.
The hyoid has its basilar part generally somewhat more convex and
enlarged than in Man; but in _Mycetes_ it becomes greatly enlarged and
deeply excavated, so as to form a great bony bladder-like structure. The
posterior cornua of the hyoid (thyrohyals) are never entirely absent, but
the anterior or lesser cornua may be so, as in _Mycetes_. The anterior
cornua never exceed the posterior cornua in length; but they may be
(_e.g._ in _Cercopithecus_) more largely developed relatively than in
Man, and may even be jointed, as in _Lagothrix_.
The lungs have generally the form of those of man; but the right lung
may have four lobes, as in _Hylobates_. The great arterial trunks in
_Simia_, _Gorilla_, and _Anthropopithecus_ are arranged as in Man. In
_Hylobates_ and the lower Apes, however, the left carotid artery may take
its origin from the innominate artery.
In regard to their distribution in time the earliest record that we as
yet have of the occurrence of Apes is in the Middle Miocene of Europe,
where forms are met with apparently so closely allied to some of the
higher existing types that it is evident we must look much farther
back before we can get any clue to the origin of the suborder. Since
all the known fossil Old World Apes are referable to the _Simiidæ_ or
_Cercopithecidæ_, and no representatives of these families have been
obtained from the Tertiaries of America, it would appear that the
distinction of the Apes of the Old World from those of the New is of very
old standing.
At the present day Apes are mainly confined to tropical and subtropical
regions. In the Old World _Macacus inuus_ is found as far north as
Gibraltar, _M. tibetanus_ and _Semnopithecus roxellanæ_ inhabit western
Tibet, while in Japan we have _M. speciosus_. In the New World one
species of _Ateles_ is known to occur as far north as latitude 19° in
Southern Mexico, and may range a few degrees higher. To the southward
species are found near the Cape, in Timor, and the Malay Archipelago;
while in America they range in Brazil and Paraguay to about latitude 30°.
The Tibetan species are found at a very high elevation; and in the outer
Himalaya the Langurs (_Semnopithecus_) may be seen in winter and spring
leaping from bough to bough of snow-covered pines.
Apes are very abundant in the Ethiopian and Oriental regions, as well as
in that part of America which extends from Panama to Southern Brazil.
Ceylon, Borneo, Sumatra, and Java may be mentioned as islands where
Ape-life attains great development; but they are unknown in Madagascar
and the West Indian Islands, and of course in the Australasian region.
We have already alluded to the circumstance that while the _Simiidæ_
and _Cercopithecidæ_ are exclusively confined to the Old World, the
_Cebidæ_ and _Hapalidæ_ are equally restricted to the New, and we may
accordingly proceed to notice a few points in relation to generic
distribution. Of the larger _Simiidæ_ the Gorilla and Chimpanzee
are confined to Equatorial Africa, and the Orang to Malayana; but
there is evidence of the former existence of a species of Chimpanzee
(_Anthropopithecus_) and not improbably of an Orang (_Simia_) in Northern
India. The Gibbons (_Hylobates_) are now exclusively Oriental. Europe
has only _Macacus inuus_ of Gibraltar, also found in Africa north of
the Sahara, and therefore strictly Palæarctic in distribution. The
Ethiopian region includes in the _Cercopithecidæ_ the genus _Colobus_
(the African analogue of _Semnopithecus_), _Cercopithecus_, and the
Baboons (_Cynocephalus_, etc.) The Baboons range, however, into Arabia
and Syria, and also existed during the Pliocene epoch in Northern
India. _Semnopithecus_ and _Macacus_ are very characteristic of the
Oriental region; but, as already mentioned, outlying species extend into
various parts of the Palæarctic region. _Macacus_ has indeed a very
wide distribution, extending from Gibraltar and North Africa to Japan.
The allied _Cynopithecus_, represented only by _C. niger_ of Celebes,
approximates to the Baboons; while the one species of _Nasalis_ is
peculiar to Borneo. Remains of _Semnopithecus_ and _Macacus_ occur in the
Tertiaries of India and Europe, which also yield allied extinct types
noticed in the sequel.
In America, north of Panama, the genera known to be represented are
_Chrysothrix_, _Nyctipithecus_, _Cebus_, _Ateles_, _Mycetes_ and _Hapale_
in Veragua; _Nyctipithecus_, _Cebus_, _Ateles_, and _Mycetes_ in Costa
Rica and Nicaragua; _Ateles_ and _Mycetes_ in Guatemala; and _Ateles_
in Southern Mexico. Brazil is the headquarters of the American Apes;
but different portions of that vast region have a somewhat distinct
Ape fauna. Thus the genus _Eriodes_ appears in South-Eastern Brazil
to represent the species of _Ateles_ inhabiting the more northern and
western parts of the empire. Southwards, the genera _Cebus_, _Mycetes_,
_Chrysothrix_, and _Callithrix_ extend farthest; but they do not probably
all extend to the farthest limit yet known, namely 30° S. The species
found farthest south are _Mycetes caraya_, _Cebus fatuellus_, and
_Callithrix personatus_.
_Family_ HAPALIDÆ.
Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ²⁄₂; total 32. No bony external
auditory meatus, a broad internarial septum, and no cheek-pouches. Tail
non-prehensile; no ischiatic callosities. Pollex not opposable; a long,
curved, and pointed claw to all the digits except the hallux.
This family, which includes the smallest representatives of the suborder,
commonly known as Marmosets, is confined to the New World. In addition
to the diagnostic characters given above, it may be mentioned that the
pollex is elongated and the hallux very small, while the pectoral limbs
are not longer than the pelvic pair; and the tail is long and more or
less thickly covered with elongated hairs.
The dentition of the Marmosets sufficiently distinguishes them from all
other members of the suborder, although they are evidently nearly allied
to the _Cebidæ_. The small size of the hallux, and the total incapacity
of the pollex to oppose itself in the least degree to the other digits,
as well as the presence of claws on all the digits of the manus, are,
however, equally characteristic features. These animals (Fig. 337) are
not larger than Squirrels, and are of active arboreal habits, living
in small companies, and adding insects to the ordinary fruit diet.
Frequently, as in the figured species, the head is furnished on either
side with a long tuft of hair projecting outwards and backwards. They
give birth to as many as three young ones at a time, and thereby differ
from all other members of the suborder, in which one is the normal
number. They are divided into two genera, according to the proportionate
size of the lower canine to the incisors; but some species present an
intermediate condition, so as to render this distinction of somewhat
doubtful value.
_Hapale._[664]—Lower canine not longer than the incisors. A number of
species have been described, among which may be mentioned _H. jacchus_,
_H. albicollis_, _H. aurita_, and _H. humeralifer_. Remains of species of
this genus have been found in the cavern-deposits of Brazil.
[Illustration: FIG. 337.—The Golden Marmoset (_Midas chrysoleucas_). From
_Proc. Zool. Soc._ 1868, pl. 24.]
_Midas._[665]—Lower canine considerably longer than the incisors. No
less than twenty-four species of this genus have been named, among
which the Silky Marmoset (_M. rosalia_) of Columbia, the Pinche Monkey
(_M. œdipus_) of South-Eastern Brazil, and the Golden Marmoset (_M.
chrysoleucas_, Fig. 337) are well-known types.
_Family_ CEBIDÆ.
Dentition: _i_ ²⁄₂, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ³⁄₃; total 36. Tail frequently
prehensile; digits with nails; other characters as in the _Hapalidæ_.
The members of this American family are at once distinguished by the
dental formula, which is numerically higher than in any other Apes.
The various species range over the whole of tropical America, but are
most abundant in the dense forest regions of Brazil, where they live
a completely arboreal life, to which the prehensile tails of many of
them are so specially adapted. They are in most respects closely allied
to the _Hapalidæ_, but the pollex diverges somewhat from the plane of
the other digits; while the retention of the third molar is a very
distinctive feature. None of the species attain the dimensions of the
larger _Cercopithecidæ_ of the Old World. The genera are usually arranged
in five subfamilies.
Subfamily =Mycetinæ=.—Lower incisors vertical; hyoid bones enormously
inflated; tail long and prehensile, naked beneath at the end; pollex well
developed.
[Illustration: FIG. 338.—Side view of skull and hyoid bone of the Red
Howling Monkey (_Mycetes seniculus_). From De Blainville.]
_Mycetes._[666]—The sole representatives of this subfamily are the
well-known Howling Monkeys, all of which are included in the genus
_Mycetes_. They are of more bulky build, and have more produced muzzles
than the other members of the family. The truncated occipital region, and
the extraordinary development of the rami of the mandible, especially
of their angular and ascending portions, are the chief peculiarities
by which the skulls (Fig. 338) of the members of this genus are
characterised. The last named character, which is more marked in the male
than in the female sex, is related to the enormous size of the vocal
organs, which the rami of the mandible enclose and protect. The inflated
hyoid bone, which forms a deep cup, is shown in the figure. The Howlers
are subject to great individual and sexual variation of colours, so that
the discrimination of species from local races is difficult. In one
species the male is black and the female straw-coloured; and several of
the species have bright red or golden hair on the flanks. In disposition
these creatures are sluggish and stupid, but their chief characteristic
is their prodigious power of voice. Mr. Bates, in his _Naturalist on the
Amazons_, observes that “when Howlers are seen in the forest there are
generally three or four of them mounted on the topmost branches of a
tree. It does not appear that their harrowing roar is emitted from sudden
alarm; at least it was not so in captive individuals. It is probable,
however, that the noise serves to intimidate their enemies.”
Several species have been described, the Red Howler (_M. seniculus_) and
the Ursine Howler (_M. ursinus_) being well-known forms. Remains of this
genus probably referable to existing types are found fossilised in the
cavern-deposits of Brazil. An allied fossil form from the South American
Pleistocene has been described as _Protopithecus_.
Subfamily =Pitheciinæ=.—Lower incisors inclined forward at their
summits; hyoid bone normal; tail long or short, non-prehensile; pollex
well developed. Two genera are included in this subfamily, readily
distinguished by the length of the tail.
_Pithecia._[667]—The Sakis, as the representatives of this genus are
commonly termed, are readily characterised by the length of the tail; the
angle of the mandible is expanded, although less so than in _Mycetes_. A
number of species have been described, the Black Saki (_P. satanas_) of
the Lower Amazons, being one of the best known. While some species, like
_P. hirsuta_, have long hair covering the whole of the head, body, and
tail, in others only the head, or the cheeks and chin, are so clothed.