However, in many countries they are feared as much or even more than the
most poisonous snakes. In the south of Spain and Portugal, for instance,
where Geckos are plentiful in and outside the houses, and are consequently
objects of daily observation, the "_osga_" is considered a dreadfully
poisonous creature. They become very tame, or rather confiding in their
regular habits, provided they are not molested. If caught–and they have
many enemies among other lizards and snakes–the only safety of these
defenceless and mostly small creatures lies in their tail, which, being
extremely brittle, is left in the claws or jaws of the pursuer. The
remaining stump soon produces a new tail, in shape and size like the old
one, but with a different and simpler scaling. I knew of several specimens
of {507}the Portuguese _Platydactylus facetanus_, which, having lost their
tails in the act of being caught, were kept in a box for six weeks without
food. On their arrival in England they had each grown a new stump nearly
half an inch long!
FAM. GECKONIDAE. SUB-FAM. 1. GECKONINAE.–Vertebrae amphicoelous; parietal
bones separate; clavicles dilated and perforated. Hereto belong the
overwhelming majority of Geckos, only a few of which can be mentioned.
_Teratoscincus scincus._–This most peculiar creature, about six inches in
length, inhabits the steppes of Turkestan and neighbouring desert-regions
of Persia. It is a thorough desert-form. The digits are devoid of adhesive
lamellae, but are granular inferiorly and strongly fringed laterally, an
arrangement which is rare among Geckos, practically restricted to it with
_Ptenopus_ and _Stenodactylus_, which are likewise deserticolous. This is a
beautiful illustration of adaptation to the surroundings. A Gecko, instead
of climbing rocks and trees, has lost the climbing apparatus, or has
transformed parts of it for running upon loose sand. The body is covered
with imbricating, rather large and smooth scales. The tail is round at the
base, compressed in its posterior half, covered below and on the sides with
scales like those of the body, but on the upper side with a series of
large, transverse, nail-like plates. By rubbing these plates upon each
other, this Gecko produces a shrill, cricket-like noise, sitting at night
in front of his house, perhaps in order to attract grasshoppers. The noise
is made by both sexes.
_Ptenopus_, a Gecko of Damara Land, likewise adapted to desert-life,
produces a similar chirping noise by its throat.
_Phyllodactylus_ is a genus of world-wide distribution, occurring in
tropical America, Africa, Madagascar, and Australia, extending to the
Norfolk Islands and to Lord Howe's Island. One species, _Ph. europaeus_,
occurs on the islands in the Western Mediterranean. The digits are
furnished with transverse lamellae, the greater number of which are broken
up into small scales forming three longitudinal series. The ends of the
digits are dilated, with two large plates inferiorly, separated by a
longitudinal groove into which the claw is retracted. The upper parts of
the body are covered with juxtaposed scales intermixed with larger
tubercles. The abdominal scales are small and imbricating. The cylindrical,
tapering tail is slightly prehensile, covered with {508}small scales
arranged in verticils. This species is devoid of femoral or anal pores.
General colour above grey-brown, with darker and lighter markings; a dark
streak on the side of the head, passing through the eye. Under parts
whitish. Total length up to 3 inches. The eggs are almost round, measuring
8.7 by 7 mm.
[Illustration: FIG. 120.–_Hemidactylus turcicus_ (left), and _Tarentola
mauritanica_ (right). × 1.]
_Hemidactylus_, likewise a widely distributed genus, with many species. The
digits are dilated, inferiorly with two rows of lamellae; the clawed joints
are slender, bent at an angle, and rising from within the extremity of the
dilated portion. _H. turcicus_, between 3 and 4 inches long.–The upper
parts of the body are covered with minute granules, mixed with larger
tubercles. The abdominal scales are small and slightly imbricating. The
male has several pre-anal pores. The tail is covered above with minute
scales and tubercles, below with a series of large transversely dilated
plates. The general colour is white below, brown above, with darker spots,
and with white specks on many of the tubercles. This species extends from
{509}Southern Portugal and Spain to Karachi. Like _Phyllodactylus_ and
various other kinds of Geckos, the body is semi-transparent; so much so
indeed that the white eggs shimmer through the body in certain lights.
_Tarentola mauritanica_ s. _Platydactylus facetanus_.–The digits are
strongly dilated, with undivided lamellae below, and a flat, nail-like
scute on their upper surface near the tip. Only the third and fourth digits
are clawed. Femoral or pre-anal pores are absent. The upper parts are
covered with scales and granules, and bear several longitudinal rows of
strongly keeled, large tubercles; the under parts have hexagonal scales.
General colour above greyish-brown, with darker or lighter markings; with a
dark streak through the eye. Total length of large males about 6 inches.
This species is one of the commonest Geckos in the Southern Mediterranean
countries. In Portugal it extends northwards to the Douro. It has been
introduced by ships into the ports of Cette, Toulon, and Marseilles. It is
easily kept in captivity, like most Geckos indeed, provided they are
supplied with a variety of insect-food, water in the shape of drops, and
suitable places to hide in. A female, which I had received from Algiers in
a little tin box, with a lump of meat (presumably its food!), laid two eggs
six weeks after its arrival. This was towards the end of April. Towards the
end of June in the same year it again laid two eggs, measuring 13 × 10 mm.
Another specimen laid in June in two successive years. These and other
Geckos live very well in a greenhouse, or in a large glass cage. They
change colour most adaptively. They hunt preferably at night for insects,
which are stalked and then suddenly rushed at. Drops of water are taken by
a lapping motion of the tongue. For sleeping-places they selected bits of
hollow bamboo, but these had to be vacated when some tree-frogs crept into
them for the daytime, and the Geckos took to some curved pieces of bark, on
the under side of which they slept, with their backs downwards. This is, by
the way, a favourite position of rest of most Geckos. But _Stenodactylus
guttatus_ of Egypt lies flat on its belly, tucks the fore-feet under and
inwards like a cat, rests the head upon them, and stretches the hind-limbs
out backwards. The little Geckos are rather intelligent. They take no
notice of a finger put against the other side of the glass to which they
happen to cling; but {510}when the hand is put inside their cage and
approaches them too near, they dart off suddenly. When driven into a corner
they wriggle and wag their tails, or even raise the latter, perhaps as an
invitation to grasp it, in which case it would of course break off. When
caught, they emit feeble sounds, and attempt to bite with the mouth widely
open. During the moulting, which takes place at least twice a year, in the
spring and in the autumn, the skin peels off in flakes; if, as happens
sometimes, the skin upon the lamellae is not stripped off neatly, these
refuse to act, and the creature cannot climb until all the old skin has
been rubbed off.
In their native haunts they are very regular in their habits. Favourite
resorts of theirs are old olive trees or oak trees, the rough and cracked
bark of which affords excellent places for hiding in. Hollow trees are of
course preferred. Not a single specimen is seen during the early hours of
the morning or in the forenoon; but when the sun has become broiling hot,
and our own shadow passes over the stem of a tree, we become aware of
flitting little shadows which jerk over its surface. These are Geckos which
had been basking, motionless; very dark grey, almost blackish, just like
the colour of the grey bark upon which the last wet season's moss has been
scorched to a black cinder. It is difficult to espy a Gecko whilst it is
glued on to such a tree. Only the little beady eyes betray it, watching you
carefully. Nothing appears more easy than to catch that motionless thing.
You put out your hand and it is gone; like a flash it has moved a foot
higher up, or down, to the right or to the left, just where you least
expected it to go, and there it clings on motionless as before. It does not
seem to run; it glides along, dodging over to the other side of the stem
and back again. There is system in its motions, since, taking a last
leisurely look around, it gently disappears in a rent or hole. Towards the
evening, or when the shadows become longer, the Geckos become lively. One
after another appears on the surface, upon the tree, or at the entrance of
the cave, and they all move about in their peculiar rushing jerks. Spiders,
flies, mosquitoes, moths, form the principal diet, and the hunting goes on
well into the night. Where a gecko has been seen once it is sure to
reappear the next day at the same hour. Those which take up their abode
inside a house become almost domesticated. They are strange sights when
hunting for flies, {511}running up and down the papered walls; but we
fairly gasp when they come to the upper corner, calmly bend over, and with
the next jerk slide along the white-washed ceiling. We are accustomed to
flies performing such feats, but at animals five inches long, supple and
fat, we are inclined to draw the line. However, that is the way of Geckos,
and–be it confessed–the more we ponder over the mechanism of their fingers
and toes, the less we comprehend how such little vacua can support or
suspend such heavy creatures from a dry and often porous surface.
_Gecko._–The digits are strongly dilated with undivided lamellae. All,
except the pollex and hallux, have a very short compressed terminal phalanx
with a retractile claw. Males with femoral or pre-anal pores. This Eastern
genus includes some of the largest of all Geckos.
_G. stentor_ of the Malay countries reaches a length of 15 inches. _G.
verticillatus_ s. _verus_ s. _guttatus_ ranges from Eastern Bengal to China
and through the Indian archipelago. It grows to about one foot in length.
The head is large; the back is covered with small granules and about a
dozen rows of large tubercles. The tail, when intact, and the belly are
covered with scales, those of the tail being arranged in transverse rows,
several of which make up distinct rings. The upper parts of the body are
grey or yellowish with red spots and vermiculations. According to
Theobald[151] it lays about eight hard-shelled white eggs as big as a
musket-ball, cementing them to trees, rocks, or secluded buildings. The cry
is "touk-tay," several times repeated, and ending in a long-drawn out,
diminuendo, guttural rumble. This animal does not confine itself to
insects, but eats young rats also. Dr. Mason has seen it devour smaller
species of house-lizards, and Theobald has seen it seize a bat flying round
the room, and devour it.
Tennent[152] tells the following story about one of these creatures: "In an
officer's quarter in the fort of Colombo, a Gecko had been taught to come
daily to the dinner-table, and always made its appearance along with the
dessert. The family were absent for some months, during which the house
underwent extensive repairs, the roof having been raised, the walls
stuccoed, and the {512}ceilings whitened. It was naturally surmised that so
long a suspension of its accustomed habits would have led to the
disappearance of the little lizard; but on the return of its old friends,
it made its entrance as usual at their first dinner the instant the cloth
was removed."
_Ptychozoon._–The digits have the same structure as described in the genus
_Gecko_, but they are entirely webbed. The extraordinary feature of
_Ptychozoon_ is the membranous expansions on the sides of the head, body,
limbs, and tail, which are said to act as parachutes. _P. homalocephalum_,
the only species, inhabits the Malay Islands and the Malay Peninsula. It
reaches a length of 8 inches. A specimen obtained by F. H. Bauer in Java,
in the month of November, laid two eggs a few days after its capture. One
young was hatched in the middle of the following May, and two days later
another came out of the second egg. The characteristic folds of the skin
were already clearly discernible.
SUB-FAM. 2. EUBLEPHARINAE.–Differing from the true Geckos by their
procoelous vertebrae and the fusion of the two parietal bones into one. The
eyelids are not reduced, but remain functional. This sub-family is
undoubtedly a heterogeneous assembly, as indicated by the very scattered
distribution of its few species (about seven), in India, West Africa, and
Central America.
[Illustration: FIG. 121.–_Ptychozoon homalocephalum._ × ⅔.]
SUB-FAM. 3. UROPLATINAE, composed of a few species of the genus _Uroplates_
in Madagascar. The distinctive characters of {513}these otherwise typical
Geckos are the fusion of the nasal bones into one, the small size of the
interclavicle, and the non-dilated shape of the clavicles.
Neither the Eublepharinae nor the Uroplatinae are more nearly related to
other Autosauri than are the other Geckos. They are modifications within
the sub-order of the Geckones.
SUB-ORDER 2. LACERTAE.–_Autosauri with procoelous, solid vertebrae, and
with the ventral portions of the clavicles not dilated._
Cope,[153] discarding outer appearances as deceptive in the classification
of the Lacertae, laid stress upon internal characters, notably the presence
or absence of osteoderms, the formation of the skull, and the structure of
the tongue. Boulenger[154] has followed and improved upon Cope's
arrangement, and has elaborated the classification, which, being used by
himself in the three volumes of the Catalogue of Lizards in the British
Museum, has also been followed in the present work, with slight alterations
in the order of treatment of the families. For our present purpose we
diagnose the families as follows, giving preference to such characters as
are most easily ascertained:–
SYNOPSIS OF THE FAMILIES OF LACERTAE.
Fam. 1. Agamidae. Acrodont. Tongue broad and thick. No
osteoderms. Old World, p. 515.
Fam. 2. Iguanidae. Pleurodont. Tongue short and thick. No
osteoderms. America, Madagascar, Fiji
Islands, p. 528.
Fam. 3. Xenosauridae. Pleurodont, solid teeth. Anterior part of
tongue retractile. No osteoderms on the body.
Mexico, p. 536.
Fam. 4. Zonuridae. Pleurodont. Tongue short, not retractile. With
osteoderms at least upon the skull, where
they roof in the supratemporal fossae.
African sub-region, p. 536.
Fam. 5. Anguidae. Pleurodont, solid teeth. Anterior part of
tongue emarginate, retractile into the
posterior portion. Osteoderms on body and
head, roofing over the supratemporal fossae.
Limbs mostly reduced. America, Europe, India,
p. 537.
Fam. 6. Helodermatidae. Pleurodont, lower teeth grooved, with poison-
glands. Tongue bifid. Osteoderms tiny.
Postfronto-squamosal arch absent, p. 540.
Fam. 7. Lanthanotidae. Pleurodont. Tongue short and bifid. {514}
Postfronto-squamosal arch absent. No
osteoderms. Borneo, p. 541.
Fam. 8. Varanidae. Pleurodont. Tongue very long, bifid, smooth,
very protractile. No osteoderms. Postorbital
and temporal arches incomplete. Old World,
p. 542.
Fam. 9. Xantusiidae. Pleurodont. Tongue very short and scaly. No
osteoderms. Supratemporal fossa roofed over
by the cranial bones. No movable eyelids.
Central America and Cuba, p. 547.
Fam. 10. Tejidae. Teeth solid, almost acrodont. Tongue long,
deeply bifid, with papillae. No osteoderms.
Limbs sometimes reduced. America, p. 547.
Fam. 11. Lacertidae. Pleurodont. Tongue long, bifid, with papillae
or folds. With osteoderms on the head.
Supratemporal fossae roofed over by the
cranial bones. Old World, p. 549.
Fam. 12. Gerrhosauridae. Pleurodont. Tongue long, with papillae, but
feebly nicked. With osteoderms on the head
and body, roofing over the supratemporal
fossae. African sub-region, p. 559.
Fam. 13. Scincidae. Pleurodont. Tongue scaly, feebly nicked.
Osteoderms on the head and body. Limbs
often reduced. Cosmopolitan, p. 559.
The following five "families" are much degraded in conformity with their
usually subterranean life, see p. 496:–
Fam. 14. Anelytropidae. Without limbs. Body covered with scales.
Mexico and Africa, p. 564.
Fam. 15. Dibamidae. Vermiform, limbless body covered with scales,
without osteoderms. Australasia and Nicobar
Islands, p. 564.
Fam. 16. Aniellidae. Without limbs; body covered with scales,
without osteoderms. California, p. 564.
Fam. 17. Amphisbaenidae. The body is covered with soft skin, forming
numerous rings with mere vestiges of scales.
Without limbs, except _Chirotes_ with four-
clawed fore-limbs, p. 565.
Fam. 18. Pygopodidae. Snake-shaped, with scales. Fore-limbs absent,
hind-limbs appearing as a pair of scaly
flaps. Australia, p. 567.
These eighteen "families" of the Lacertae fall into four main groups. We
naturally assume that the presence of osteoderms and of complete cranial
arches indicate more archaic conditions than their absence, just as we
conclude that limbless forms have been evolved from creatures with fully
developed limbs. We arrange the four groups with their families as
follows:–
{515}Group I. Zonuridae and Anguidae assume a central position, with
Iguanidae and Agamidae as two parallel families of highest development.
Aniellidae as the most degraded forms. Helodermatidae and Lanthanotidae
as rather primitive and solitary survivals.
Agamidae Iguanidae
| |
| Xenosauridae
| |
Zonuridae–Anguidae–Helodermatidae.
|
V
Aniellidae.
Group II. Xantusiidae–Tejidae–Amphisbaenidae.
Group III. Scincidae–Gerrhosauridae–Lacertidae.–Here also Anelytropidae
and perhaps also Dibamidae as degraded Scincoids.
Group IV. Varanidae, which are in many respects the most highly developed
of all.
Pygopodidae are of obscure relationship.
[Illustration: FIG. 122.–Map showing the distribution of the Agamidae.]
FAM. 1. AGAMIDAE.–Acrodont, Old-World Lizards, with a broad and short
tongue. The teeth are usually differentiated into incisors, canines, and
molars. The orbit is closed posteriorly; the temporal fossa is bridged over
by an arch which is formed chiefly by the squamosal and the well-developed
jugal; the postorbital mostly remaining small, and the postfrontal and
supratemporal bones being either absent or not present as separate
elements. The limbs are well developed. The eye, provided with complete
eyelids, is distinctly small and has a round pupil. The skin is devoid of
osteoderms, although large and numerous spines are often present,
especially on the head and on the tail. The Agamidae, of which about two
hundred species, arranged {516}in about thirty genera, are known, exhibit a
great diversity of mostly flat-bodied, terrestrial and more laterally
compressed, arboreal forms. The majority are insectivorous, a few Agamas
have a mixed diet, while _Uromastix_ and some others are chiefly, if not
entirely, frugivorous and herbivorous. They are an exclusively Old-World
family, avoiding the cooler parts of the Palaearctic sub-region, and also,
a very curious fact, Madagascar. The majority live in Australia and in the
Indian and Malay countries, comparatively few in Africa, chiefly the genus
_Agama_.
[Illustration: FIG. 123.–_Draco volans._ × ⅔.]
_Draco_ ("Flying Dragon").–The body is much depressed and the sides extend
as a pair of large wing-like membranes, which are supported by five or six
of the much-elongated posterior ribs, and can be folded up like a fan. On
the throat are three pointed appendages, a short one on either side and a
long one in the middle. The tail is very long and slender, but not brittle.
About twenty species of this extraordinary genus inhabit the various
Indo-Malayan countries; one, _D. dussumieri_, occurs in Madras. _D. volans_
of the Malay Peninsula, Sumatra, Java, and Borneo is about 10 inches long,
5 of which are taken up by the tail. The {517}male has a small nuchal
crest. The upper parts of this pretty creature have a metallic sheen, with
small dark spots and undulating cross-bands upon the rich brown
ground-colour. The wings are orange with black markings. The gular sac of
the male is orange, that of the female is blue.
The "Flying Dragons" use their wings as parachutes, but their sailing
powers are said to be very moderate. Certainly they do not fly by moving
the wings, but when at rest upon a branch, amidst the luxurious vegetation
and in the immediate neighbourhood of gorgeously coloured flowers, which
partly conceal them by their likeness, they greatly resemble butterflies,
especially since they have the habit of opening and folding their pretty
wings.
_Ceratophora._–This exclusively Ceylonese genus is remarkable for a
flexible, erect, and pointed appendage which arises from the top of the
snout; it is best developed in the males, vestigial or absent in the
females. Gular appendages are absent. The trunk is crestless, slightly
compressed, and covered with partly keeled scales. The tail is slender and
very long, about two-thirds of the total length of the animal. The general
colour is olive-brown, with irregular darker markings and with light
streaks on the head and thighs. _C. stoddarti_ and _C. tennenti_ are about
10 inches long, the former without, the latter with, little scales upon the
rostral appendage.
_Lyriocephalus_, with _L. scutatus_ (Fig. 124) of Ceylon as the only
species, is remarkable for its Chameleon-like appearance. A splendid case
of convergent evolution, but most improbably of mimicry. The tympanum is
quite hidden. The head is raised into a pair of sharp bony edges. On the
top of the nose is a thick globular lump, recalling the genus
_Ceratophora_, and also various Malagasy Chameleons. The back and sides are
covered with very small granular scales, intermixed with several rows of
enlarged scales as in _Chameleo pumilus_, and there is a serrated crest
along the back from neck to tail. The under parts are covered with large
keeled scales with sharp points directed backwards, especially on the tail.
The whole body is laterally compressed. The pollex and the fifth toe are
strongly opposed to the other digits. The general colour is greenish above,
whitish below. Total length about one foot.
_Calotes_, with many species in India and in the Malay Islands, is
distinguished by a crest on the neck and back. Many of the males have a
gular sac. The tail is extremely long. These lizards are remarkable for
their changes of colour.
{518}[Illustration: FIG. 124.–_Lyriocephalus scutatus._ × ⅔.]
_C. versicolor_ ranges from Afghanistan through the whole of India to
Southern China, and attains a length of 14 inches, 11 of which are taken up
by the tail. It possesses no gular sac, but has a well-developed crest. The
whole body and tail are covered with strongly keeled scales. When the
lizard is irritated, or swallowing its food, the head and neck become
brilliant red, whilst the usually brownish tint of the body is converted
into pale yellow. Mr. Annandale has favoured me with the following
observations on _C. emma_:–"In the Malay Peninsula the Europeans misname
this lizard Chameleon. The colour-changes appear to be brought about by
emotions, although the lizard is often darker towards {519}evening than it
is at mid-day. The males are very pugnacious, and change colour as they
fight. At the time of courtship a curious performance is gone through by
the male, the female remaining concealed in the foliage hard by. He chooses
some convenient station, such as a banana leaf or the top of a fence, and
advances slowly towards the female. His colour is then pale yellowish
flesh-colour, with a conspicuous dark spot on each of the gular pouches,
which are extended to their utmost. He stands upright, raising the fore
part of the body as high as possible, and nodding his head solemnly up and
down. As he does so, the mouth is rapidly and repeatedly opened and shut,
but no sound is emitted. When he is driven away, caught or killed, the dark
spot disappears entirely from the neck. If one male is captured, another
takes his place within a few hours."
_C. ophiomachus_ of Southern India and Ceylon reaches 2 feet in length, has
a fold of skin in front of each shoulder, and is generally known as the
"blood-sucker" on account of the red colour displayed during excitement on
the head and neck.
_C. mystaceus_, chiefly in Burma and Siam, but also in the Nicobar Islands
and in Ceylon, has a small gular sac and an oblique fold in front of each
shoulder. The specific name seems to refer to the yellowish lips.
Mason[155] gives the following vivid account of it:–
"This is a very common species in gardens in Toung-ngoo. A pair made their
home in the mango trees near my study window. The female blundered into the
house a few days ago, but I found her a very unattractive animal of a
uniform earth-brown colour. The male, however, is sometimes a beauty. He
may be often seen jerking his head up and down, with the head, pouch, and
whole front of the body a glowing ultramarine blue, contrasting beautifully
with the reddish-brown of the hinder part of the body and tail. From the
nose to the shoulders, below the eye, is a broad white band, which is
interrupted by three reddish-brown patches, in line with the white band,
before reaching the uniform reddish brown of the hinder part of the body.
Occasionally the white band below the eye assumes a brownish colour, and
the animal appears to have a brown band down each side. He does not always,
however, appear in this gay dress. While I am writing, I see him coming
down the trunk of one of the trees {520}in a very faded garment. His skin
suggests a bright calico after it has been washed, whose colours succumb to
soap. The blue is there, but it is no longer the bright blue of yesterday.
It has changed to a dull light indigo colour. He runs across the grass to
the foot of another tree, and stops on the bare ground at its base, where
for a minute or more he bites with great energy at a struggling
grasshopper, and while thus exercising himself the blue fades out from his
body altogether, and his whole body takes the colour of the brown earth on
which he stands. After tarrying a minute or two he ran up the other tree,
and the dull light blue colour seemed to return to him."
_Agama_ with many species in Africa and Asia; some in South-Eastern Europe.
The body is somewhat depressed. There is a fold across the throat and a pit
on either side; the presence of a gular sac is variable. A dorsal crest is
absent or but feebly developed. The males have pre-anal pores.
_A. sanguinolenta._–The body is covered with strongly keeled and pointed
scales. On the sides of the head are a few spine-like scales. The
ear-opening is partly concealed by a fringe of spinous scales. The males
have a gular pouch. This is a typical inhabitant of the deserts and steppes
of Turkestan. Zander[156] has observed the habits and many changes of
colour of this lizard. The usual garb is earthy brown above, with somewhat
darker and rather indistinct markings. The under parts are whitish.
Sometimes the creature changes to dirty white, at other times into blackish
or grey brown. Bluish-red stripes may appear on the sides of the body; blue
lines begin to show on the throat, and ultimately the whole belly,
originally white, may become ultramarine blue. When the general tone
happens to be sulphurous yellow, blue often appears on the tail and limbs.
Brick red appears on four longitudinal rows of patches on the sides of the
body. Sometimes the whole animal assumes a vinous tinge, or it is at first
greenish before turning into blue. The change begins on the tail and limbs,
extends over the head, and at length reaches the back. Red appears in both
sexes, more frequently in the female; blue almost entirely in the male.
Sunlight and warmth only intensify the colours. Adaptive coloration,
besides the usual sandy garb, has not been observed. The lizards live on
soil which is baked as hard as bricks, or in {521}cavities of old walls,
provided there is vegetation. They require vegetable food, besides insects,
grazing on grass, and having a fondness also for _Mesembryanthemum
cardiforme_. Very large males reach a total length of one foot. They are
pugnacious, especially during the time of breeding. The male inflates its
gular sac into the size of a walnut, stands up upon its four limbs, with
its head slightly lowered and turned to one side. Then it darts upon the
foe which it has been eyeing for some time.
[Illustration: FIG. 125.–_Agama stellio._ × ½.]
_A. stellio_ is the commonest Agama in Egypt, Asia Minor, and in some of
the Grecian Islands, where the Greeks still call it _korkordilos_, just as
they did in the time of old Herodotus. The Arabic name is _hardun_. This
lizard is easily recognised by the irregular folds on the neck, which are
beset with spinous horny scales. It grows to a length of 15 inches. The
general colour is brown, with dark patches on the back. When basking they
become almost black; in the breeding season the male assumes red tints on
the head and neck.
_Phrynocephalus._–This is a typical Agamoid of the steppes and deserts of
Asia. The head is short and thick, the ear is {522}hidden. The body is
depressed, devoid of a dorsal crest; on the throat is a transverse fold but
no sac.
A. Zander[157] has made interesting observations upon the habits of several
species.
_Ph. helioscopus_ lives on hard stretches of soil, which are absolutely
bare of vegetation, the soil being baked as hard as a paved road. The
lizards live on any insects they can get hold of, chiefly, however, upon
mining ants. When chased they run with short jerks, carrying the tail high
or rolled up.
_Ph. interscapularis_ occurs, in Transcaspia, on the shifting, loose sand.
It runs so fast that one scarcely sees anything but its shadow. The tail is
rolled upwards. With short jerks it suddenly changes its direction, stops
behind a few blades of grass, or in the open, makes a few shaking, wavy
movements, and covers itself lightly with sand. Shortly after that the top
of the head appears, the grains of sand rolling off between the strong
supraciliary ridges, and the little creature, only about 3 inches long,
peeps out of its temporary hiding-place.
_Ph. mystaceus_, which inhabits Transcaspia and parts of Southern Russia,
often faces its aggressor, raising itself upon its fore-limbs, curling and
uncurling its tail in its excitement, and holding its mouth widely open.
The creature, which attains a length of 9 inches, inclusive of the long
tail, then assumes a markedly changed aspect. The flaps of skin at the
corners of the mouth swell up into a half-moon-shaped transverse plate, the
hinder surface of which is covered by the outer skin, while the front is a
continuation of the rosy lining of the mouth, which thereby appears hugely
enlarged. When biting it hangs firmly on to the finger. This frightening
attitude is interesting, since it occurs in a much more developed condition
in the following genus.
_Chlamydosaurus kingi._–This peculiar Agamoid, which inhabits Queensland
and Northern and North-Western Australia, is easily recognised by the large
frill-shaped dermal expansion on either side of the neck. The two halves
are confluent on the throat. The whole frill can be erected, and is worked
by the much-elongated arches or horns of the hyoid apparatus, which extend
into the flaps of skin, somewhat like the ribs of an umbrella. The
specially modified hyoidean muscles spread out {523}and fold the frill.
When this curious creature is pursued it folds the frill and runs in a
semi-erect position upon its hind-limbs, with its fore-limbs hanging down.
However, it cannot keep up this peculiar gait for long, and it then
suddenly turns to bay, frequently at the root of a tree, which it can climb
with ease. When standing at bay it spreads out the shield to its full
extent, in the middle of which appears the widely opened mouth, which is
red inside and armed with powerful teeth. Altogether this lizard presents a
formidable aspect, and is an enemy not to be despised, considering that it
is strongly built and grows to nearly 3 feet in length. For a further
account of the habits and of the mechanism of the frill see De Vis.[158]
[Illustration: FIG. 126.–_Chlamydosaurus kingi._ × ¼.]
_Physignathus._–This is a water-loving genus, inhabiting well-watered
districts with luxuriant vegetation in Australia, Papuasia, Siam, and
Cochin China. The body and the very long tail are laterally compressed and
furnished with a low, serrated crest. _Ph. lesueuri_ of Queensland reaches
a length of about 18 inches. The general colour is dark olive above, with
darker and lighter {524}cross-bands, and with a broad black band reaching
from the eye to the shoulder. The under parts are pale olive, with small
black dots. The throat, although devoid of a special sac, is frequently
bulged out by the hyoid apparatus, as shown in Fig. 127, taken from a
specimen in the Zoological Gardens in London.
_Uromastix_ is a typical desert-form, inhabiting the dry and sandy tracts
of North Africa, Arabia, Syria, Persia, and North-Western India. The genus
is easily recognised by the short and thick tail, which is covered with
whorls of large spinous scales, while the much-depressed body and head are
almost smooth, being covered with very small scales. The tympanum of the
ear is quite exposed. The incisors are large, uniting in the adult into one
or two pairs of large cutting teeth, separated from the molars by a
toothless space. There is a transverse fold on the throat. Pre-anal and
femoral pores are well developed.
[Illustration: FIG. 127.–_Physignathus lesueuri._ × ⅓.]
These "Spiny-tailed Lizards" live chiefly upon vegetable food, leaves,
grass and fruit, but they vary this diet with insects, at least in
captivity, where they become rather partial to meal-worms. They are
absolutely terrestrial and diurnal, preferring sandy places, where they
bask or rather roast themselves in the sun; for the night, at the approach
of rain, or on dull and chilly days, they retire into their burrows, which
they dig in {525}the sand or in the hard ground, unless they hide in the
cracks of rocks. They have a regular mania for digging with their strong
limbs and short, curved claws. Although they love a great amount of heat,
and become stiff when cooled down to about 16° C. = 60 F., they can stand
several degrees of dry frost without injury. During the cold season they
hibernate. The spiny tail is used for defence. The lizard lies as a rule in
such a position in its hole that the tail blocks the narrow passage; when
touched with the hand it deals out jerky side-blows with the tail. The bite
is deliberate and very painful.
_U. hardwicki_ is a native of North-Western India and Beluchistan,
occurring especially in Sindh and Rajputana, for instance near Delhi and
Agra. This species is of a delicate sandy colour, with dark dots or
vermiculations, interspersed, occasionally, with pale blue specks. The
under parts are whitish on the tail with a greenish hue. A distinctive and
obvious mark is a large blackish patch on the anterior side of the thigh.
Total length up to one foot.
I have several times received consignments of the Indian Spiny-tailed
Lizard through the kindness of friends, but I must confess that they are
far less easily kept than one is led to believe from certain exaggerated
accounts. They are lovely, most interesting, and surprisingly tame
creatures. I received one lot in the month of June. They made burrows in
the dry soil, basked in the sun and on the grassy sods of their roomy cage,
and showed great curiosity. When approached, they at first scrambled off or
sank down flat, shut their eyes and feigned death. They then opened their
tiny yellow eyes a little, while others peeped out of their retreats to see
if all was safe, or attracted by some noise. Soon they became so tame that
they crawled over my hand. But the difficulty consisted in feeding them.
They greedily lapped up drops of water. Their dung consisted of the
indigestible parts of some species of _Equisetum_ or Mare's tail, mixed
with fragments of beetles and ants. Lettuce, cabbage, cauliflower, grass,
the flowers of red and white clover, Mare's tail, wheat, rice, and Indian
corn were offered, but they only took a few blades of grass and the hard
Indian corn, besides meal-worms. This is all the more astonishing since
other specimens are known to partake freely of herbaceous food. None of
them survived the late autumn, and most of them succumbed to a disease
{526}known as intussusception of the gut. They certainly could not complain
of the want of heat, since the bottom of their cage was kept permanently
warm by a lamp, and in the autumn they invariably slept in the warmest part
of the soil, avoiding the cool regions which would have given them a chance
of hibernating.
Another consignment arrived in the month of February. None of them ate
anything or survived the early summer.
[Illustration: FIG. 128.–_Uromastix acanthinurus._ × ¼.]
_U. acanthinurus_ and _U. spinipes_ are common in Algeria, Tunis, and
Egypt, where they prefer sandy and rocky localities. Their Arabic name is
_Dab_. In Algeria they are sometimes called "lézards des palmiers," perhaps
because they eat dates, besides berries, grass, and various flowers. Very
large specimens attain a length of 18 inches. Like the other species of
_Uromastix_ they have no voice. The African species can change colour to a
great extent. At a low temperature they are mostly grey or brownish black
above, dirty white below. When it is warmer they change to lighter shades
of brown or even to orange yellow and to green, with black or brown specks
and vermiculations. {527}A young specimen of _U. acanthinurus_ has been
observed to grow within twelve months from 90 to 150 mm. in length.
_Moloch._–The mouth of this peculiar-looking creature is very small; the
lateral teeth of the upper-jaw are implanted horizontally and directed
inwards. The body is much depressed, and, like the short tail and head, is
covered with small scales or tubercles intermixed with large spines. _M.
horridus_, the only species, inhabits the sandy districts of Western and
Southern Australia. Nothing is known about its habits except that it seems
to live upon ants. Its extremely rough skin is, according to an accidental
observation by Dr. Willey, highly hygroscopic. He happened to put a live
specimen into a shallow dish with water, when, to his surprise, the water
was sucked up as by blotting-paper.
[Illustration: FIG. 129.–_Moloch horridus._ × ⅔.]
_Liolepis._–The body is depressed, without a crest, and is covered with
minute granular scales. The tail is long, and has small keeled scales.
There is a strong transverse gular fold, and a fold along the side of the
body. The tympanum is distinct. Femoral, but no pre-anal, pores are
present.
_L. belli_, the only species, about 18 inches long when full grown, is a
native of South-Eastern Asia. The general colour is brownish, with pale
black-edged spots along the back; the sides are marked with black and
orange vertical bars; the under parts are orange, variegated with blue.
Annandale remarks that this is perhaps the commonest lizard on the barren
stretches of sand in Lower Siam, especially near the coast. It is
exceedingly active and timid. Though its colour is brilliant, the green and
{528}grey eye-like spots which ornament its back, and the orange and purple
stripes on its sides, are not conspicuous amidst the natural surroundings,
the former harmonising with the shadows cast upon the sand by the scanty
vegetation which it supports, and the latter being more or less concealed
by the folds into which the skin that covers the ribs naturally falls. When
the male is roughly handled and is unable to use its powerful jaws, it
flattens its body in such a way that the stripes become most conspicuous.
The female is unable to do this with such effect, as her ribs do not seem
to be so mobile and her colours are less bright. _Liolepis_ lives in holes
in the ground, which often go down vertically for more than 2 feet before
there is a bend in their course. Each burrow generally contains a pair of
these lizards, which, according to the natives, are strictly monogamous.
FAM. 2. IGUANIDAE.–Pleurodont lizards with a short and thick,
non-protractile tongue; almost entirely American, with the remarkable
exception of two genera, _Hoplurus_ and _Chalarodon_ in Madagascar, and
one, _Brachylophus_, in the Fiji Islands. Most of the Iguanidae are
insectivorous, but some of the most striking forms are herbivorous, e.g.
_Iguana_, _Amblyrhynchus_, and _Basiliscus_. In their general structure the
Iguanidae closely resemble the Agamidae, from which they differ chiefly by
the pleurodont dentition. The orbit is surrounded by bone, and the temporal
fossa is bridged over by an arch which is formed by the junction of the
squamosal chiefly with the postorbital, the jugal taking as a rule less
share in the arch. Dermal ossifications are absent on the body.
There are about three hundred different species, which have been grouped
into about fifty genera, representing arboreal, terrestrial, burrowing,
semi-aquatic forms, and even one semi-marine species. Their external
appearance varies consequently within wide limits.
_Anolis_ is distinguished by the partial dilatation on the middle
phalanges, which carry a series of transverse adhesive lamellae. In its
general shape _Anolis_ resembles slenderly built and long-tailed
Lacertidae, which it may be said to represent in tropical and sub-tropical
America, inclusive of the West Indian Islands. The males have a large gular
appendage, which can be distended by the hyoid bones. _Anolis_ is an expert
climber, living in trees, or rushing about on fences or walls of houses in
search of insects; {529}most species can change colour to a great extent.
More than a hundred species are known, of which we mention only one, very
common in the Southern United States.
_A. carolinensis_ of the South-Eastern United States and of Cuba is
beautiful golden green on the whole upper surface; the gular sac becomes
vermilion when stretched; when flaccid, it is white with occasional red
lines and spots. The under parts are white. In cold weather and in
confinement this little lizard, which is scarcely 6 inches in length,
appears dark brown, sometimes with a white line along the back. The changes
of colour are very sudden. They are thoroughly arboreal, leaping from leaf
to leaf like Tree-frogs.
[Illustration: FIG. 130.–Map showing the distribution of Anguidae,
Iguanidae, and Zonuridae.]
In _Anolis_, _Polychrus_, _Hoplurus_, _Chalarodon_, _Liosaurus_, and a few
others, the posterior ribs are much elongated and imbedded in the abdominal
muscles, often reaching the medioventral line, a feature elsewhere known in
the Geckos only.
_Polychrus._–The body is laterally compressed, covered with small scales,
but devoid of crests. The digits are likewise compressed, with keeled
lamellae on the under surface and with four large scales at the base of
each claw. Both sexes have femoral pores. The male possesses a small gular
sac. A few species in Tropical America.
_P. marmoratus_ in South America, where it is often called the Chameleon on
account of its power of changing colour. The tail is nearly three times as
long as the head and body, and is covered with keeled scales. The general
colour of this arboreal creature, {530}which reaches a length of 18 inches,
is green, but the hues are very variable, and within a short time the
creature can change into dull brown, with or without blackish spots and
bands, or with whitish spots and black lines on the head and other parts of
the body.
_Basiliscus_ is remarkable for the high and erectile crests which are
developed on the back and tail of the males. The toes are bordered on the
outer side with small lobes. The limbs are long, the hind-limbs when
stretched forwards reaching the tip of the snout. Several species in
Central America and the adjoining countries to the south.
[Illustration: FIG. 131.–_Basiliscus americanus_ (male). × ¼.]
_B. americanus_ reaches the considerable length of nearly 3 feet. The male
has a crest on the top of the head, and this is produced backwards into a
leathery lobe. The back is adorned with a very high crest; the folds and
dark-coloured marks in which give, in the accompanying illustration, the
impression that the crest is supported by spines. The long tail carries a
similar crest. The general colour of the "Basilisc" is green and brown with
dark cross-bars on the back. The crest of the male is said to be red. These
creatures are very common amidst the {531}luxuriant vegetation on the banks
of the rivers of the Tierra Caliente of Mexico and in Guatemala. They lie
upon the branches of trees, preferring those which overhang the water, into
which they plunge at the slightest alarm. The high crests, being restricted
to the male sex, are not essential to their swimming; they propel
themselves by rapid strokes of the fore-limbs, letting the long rudder-like
tail drag behind. The eggs, measuring 20 by 13 mm., are laid in April or
May, and are hidden in a hole at the base of a tree. About one dozen make a
set, and they are said to be hatched within a very short time. Owing to
their being strictly herbivorous, these pretty and striking-looking
creatures do not endure captivity in Europe, unless indeed their particular
food can be procured.
_Iguana._–The body and tail are laterally compressed and are covered with
very small scales, while those on the top of the head are large. The neck
and back carry a high crest, which is composed of separate, laterally
compressed, soft spines. A similar but lower crest borders the anterior
edge of the large gular sac, which is not dilatable. The lateral teeth are
remarkable for their finely serrated or denticulated anterior and posterior
edges. Both sexes have long rows of femoral pores. Only two species in
Tropical America, absolutely herbivorous. Their delicate flesh is much
esteemed as food.
_I. tuberculata_ (Fig. 132), of South and Central America and the West
Indies, reaches a length of 5 to 6 feet. The general colour of the upper
parts is a mixture of green and blackish, frequently speckled with white or
yellow, and there is usually a pale band in front of each arm. The flanks
are marked with dark, light-edged bars. The under parts are pale greenish
or whitish. The Iguanas live in the trees, and when there is danger they
jump into the water whatever the height of the tree, coming down with
violence. In going up some of the narrow, unfrequented creeks in the
Mosquito country, according to Napier Bell,[159] the voyager often
encounters quite a shower of falling Iguanas, and runs some risk of getting
his neck broken. Large specimens, 6 feet long, weigh perhaps 30 lbs. They
burrow deep horizontal holes in the sloping side of a bank. About two dozen
eggs, nearly 2 inches long, are laid in a hole, where they are hatched in
the month of May.
{532}Iguanas are often brought to the markets, either lashed lengthwise to
a branch of the tree on which the specimen happened to be surprised, or
tied up with the long tendons of their own toes.
[Illustration: FIG. 132.–_Iguana tuberculata._ × ⅕.]
_Metopoceros cornutus_ of Hayti is closely allied to _Iguana_, but the male
has three conical horn-like scales on its head. The general colour of the
whole animal, which grows to more than one yard in length, is dull black.
The following two genera, each containing one species only, are restricted
to the Galapagos Islands. Darwin[160] gives a long and vividly written
account of their habits.
_Conolophus subcristatus._–Fully grown specimens are a yard long. Their
shape is stout, the head and fore part of the body appearing especially
heavy. The head is covered, or rather paved, with large cobble-stone-like
scales. On the neck is a low crest of recurved spines, while the median
line of the back appears simply serrated. All the teeth are trilobate. A
gular sac is absent. The coloration is striking. The head is lemon-yellow;
{533}the back is red, merging into dark brown on the flanks. The belly is
dark yellow with a tinge of reddish brown.
This lizard was found by Darwin on some of the Galapagos Islands. On James'
Island it was so common that the party found it difficult to pitch their
tent, on account of the ground being undermined by the many burrows of the
reptiles. They feed during the daytime upon the succulent cactus and the
leaves of various trees. The perfectly harmless creatures are, or were,
eaten by the inhabitants.
_Amblyrhynchus cristatus_ is closely allied to _Conolophus_, of which it
may be said to be an aquatic modification. The top of the blunt head is
covered with low, conical, broad-based scales. Over the neck, back, and
tail extends a continuous crest of low, recurved, spiny scales. All the
teeth are trilobate. The body and even more so the tail are laterally
compressed. The general colour is dark brown above, paler and inclining to
whitish below. Younger specimens have pale grey spots and blackish
cross-bands on the back and sides. Total length up to 4 feet. The
remarkable feature of this Iguanoid is its semi-marine life. It inhabits
the rocky and sandy strips of coast of most of the Galapagos Islands,
feeding upon certain kinds of algae, which it has to dive for, since these
plants grow below tide-marks.
_Phrynosoma_ ("Horned Toads").–The body of these little creatures is much
flattened and broadened, devoid of a dorsal crest, but covered with larger
and smaller, strongly keeled scales. The head is bordered posteriorly by
conspicuous osseous spines. The under parts are covered with small, very
regular scales. Both sexes have a long row of pores on the under surface of
the thighs. The general colour of the upper parts is a mixture of yellow,
grey, brown, and black, the larger spiny scales causing the animal to look
as if it were sprinkled with the dried husks of seeds, for instance those
of Buckwheat. The object is concealment, by close adaptation to the arid,
sandy localities which are the home of "Horned Toads." About one dozen
species inhabit the western half of the United States and Central America.
All the species are viviparous, almost the only instance among Iguanidae.
_Ph. cornutum_ has five spikes on each side of the head: one postorbital,
three temporal, and one occipital, the latter being by far the largest. The
sides of the lower jaw project in the shape {534}of prominent ledges, and
are protected by a series of small spines. The ventral scales are keeled.
The under parts are yellowish, frequently with a few brown spots. This
species, which grows to a length of 5 inches, ranges from Illinois through
Kansas and Texas to Northern Mexico.
[Illustration: FIG. 133.–_Phrynosoma cornutum_ ("Horned Toad"). × 1.]
_Ph. coronatum_, an inhabitant of California, has an additional smaller
spine between the two large occipitals. The scales of the belly are quite
smooth.
These peculiar-looking and interesting creatures recall some of the extinct
Dinosaurs in the curious configuration of their head: small miniatures
indeed. In order to be kept in good health, and to be observed properly,
they require, above all, warmth, sunshine to bask in, sand to burrow in,
and proper food. The latter consists of all kinds of small insects, the
necessary variety of which is best procured by making sweepings with a
butterfly-net in a meadow. They take green-flies, house-flies, ants, smooth
caterpillars, small moths, meal-worms, wood-lice, etc. The food is snapped
up very quickly by a flash of the tongue, which can be turned out, almost
like that of a frog, but only to the extent of half an inch. Water in the
shape of dew, or drops, is absolutely necessary. When in good condition,
they defaecate regularly every alternate day.
{535}[Illustration: FIG. 134.–_Phrynosoma coronatum_ ("Horned Toad"). × 1.]
They love to bask in the broiling sun, heating themselves well through; and
in the afternoon, long before sunset, when the sand is warmed up to 40° C.,
or fever-heat, they prepare to go to bed. For this they select a dry and
soft spot, and within a few minutes manage to dig themselves in flat,
literally sinking into the sand by pushing themselves forwards, and by
shovelling the sand upon their backs with peculiar motions of the fringed
sides of their flat bodies. Sometimes the spines of the head remain
sticking out, looking like dry thorns scattered over the sand. To prevent
the latter from getting into the nostrils, these are provided with
closely-fitting valves. Thus they remain concealed during the night, and
not until the sun is well up do they leave their hiding-place, first
peeping out, and then raising their head and neck, letting the sand roll
off between the spines. Still half concealed, the back covered with little
pebbles, seeds, or bits of dry leaves, they wait for a long time before
they feel lively enough to sally forth. Although mostly slow and deliberate
in their movements, stalking about with arched back, and raised upon the
fore-limbs, they can run fast enough for a few yards before they stop again
and nod in a ridiculous way. When they see themselves observed, they shut
their eyes and slowly sink {536}down. On cool and dull days they do not
appear at all, and during part of the cooler season they require artificial
heat until they are ready to hibernate. Unless they are allowed to
hibernate, they will keep on feeding through the winter, but in that case
are sure to die in the following spring.
FAM. 3. XENOSAURIDAE, with _Xenosaurus grandis_ in Southern Mexico as the
sole species, seems to connect the Iguanidae with the Anguidae. According
to Boulenger, its affinity to the former is shown by the T-shaped
interclavicle, the absence of symmetrical bony shields on the head and of
osteodermal plates on the body. Affinity to the Anguidae is indicated first
by the short tongue, which has a narrow, feebly incised, retractile
anterior part, covered with flat papillae; secondly, by the teeth, which,
instead of being hollow at the base, are solid; lastly, by the palatine
bones, which are widely separated.
_X. grandis_, scarcely one foot in length. The body is depressed, covered
above with minute granules and tubercles, below with smooth scales. A
distinct fold of skin extends from the axilla to the groin, recalling the
more strongly developed lateral fold of some of the Anguidae.
FAM. 4. ZONURIDAE.–This family, comprising four genera with about one dozen
species in South and Tropical Africa, and in Madagascar, likewise seems to
connect Iguanidae and Anguidae. It is distinguished from the former by
dermal ossifications, which roof over the supratemporal fossa; from the
latter by the tongue, the hollow teeth, and, in _Zonurus_ at least, by the
occurrence of dermal ossifications on the trunk and tail. The tongue is
short, villose, scarcely protractile, entire, or but feebly nicked at the
tip. The Zonuridae may therefore be defined as _pleurodont African lizards
with a short tongue, and with a bony roof to the supratemporal fossae_.
_Zonurus._–The whole head, back, and tail are covered with bony scales, the
horny covering of which forms very sharp spikes, especially on the tail.
The body is depressed. The ear-opening is large. South Africa, in dry and
rocky localities; one species, _Z. tropidosternum_, in Madagascar.
_Z. giganteus_ s. _derbianus_, with strong spikes on the occiput, neck, and
tail. General colour yellowish brown. Total length about 15 inches.
_Chamaesaura_ of South Africa closely approaches the {537}Anguidae by its
snake-shaped body, extremely long tail, and vestigial limbs. In _Ch. aenea_
both pairs of limbs are still present and pentadactyle, but are very small;
in _Ch. anguina_ the limbs are reduced to little styliform stumps; and in
_Ch. macrolepis_ they are altogether absent. The scales of the body and
tail are strongly keeled and imbricating, but are devoid of dermal
ossifications. Total length up to 2 feet.
[Illustration: FIG. 135.–_Zonurus giganteus._ × ¼.]
FAM. 5. ANGUIDAE.–Pleurodont lizards with osteoderms, and with the tongue
composed of two distinct portions, of which the anterior is thin,
emarginate, extensible, and retractile into the posterior thicker portion.
The supratemporal fossa is roofed in by dermal bones. The whole body is
protected by bony plates underlying the imbricating scales. The teeth vary
much in shape, but they are always solid, the new teeth not growing into
the base of the old ones, but between them. The limbs are in a very
unstable condition, there being in the family a general tendency to reduce
and lose the limbs. The shoulder- and pelvic-girdle however remain,
although sometimes merely vestigial. The tail is long, very brittle, and
easily reproduced. All the Anguidae are strictly terrestrial, and live on
animal diet. {538}Some _Anguis_, at least, are viviparous. The distribution
of the seven genera, with some forty species, is very scattered. The
majority, chiefly _Gerrhonotus_, inhabit Central America, a few occur
farther north and south–two, _Anguis fragilis_ and _Pseudopus pallasi_, in
Europe, and one in the Himalayas and in Burmah.
_Gerrhonotus_ has a pair of deep longitudinal folds, each of which extends
from the region of the neck along the side of the body towards the tail.
The four limbs are well developed and pentadactyle. The teeth are conical.
Many species, mostly in Central America. _G. coeruleus_ has the widest
range, extending from Costa Rica to Vancouver. It is also one of the
largest species, reaching a length of more than one foot. The tail is
nearly twice as long as the rest of the body. General colour above brown
with blackish bars and spots, especially on the more yellowish flanks;
under parts whitish with a greenish tinge, often with brown spots arranged
in longitudinal rows.
_Ophisaurus_ s. _Pseudopus_ is closely allied to the previous genus, being
possessed of the same kind of deep lateral folds; the limbs are, however,
reduced to a pair of tiny spikes, half concealed at the sides of the anal
cleft. The teeth are conical, and in the adult have somewhat flattened
crowns. The body and tail are very long and snake-like, but the head is
that of a typical Lizard.
_O. apus_ s. _Pseudopus pallasi_, the Glass-Snake of the Balkan Peninsula,
South Russia, Asia Minor, and Morocco, grows to more than one yard in
length, of which about two-thirds belong to the tail. The general colour is
brown above, paler below. Young specimens are olive-grey with dark brown
cross-bands on the back. _O. gracilis_ inhabits the Eastern Himalayas and
Burmah, the others live in North America.
The "Glass-Snake" inhabits bushy localities, where it can hide under the
fallen leaves and in the sand; it cannot climb, and avoids the water. Its
movements resemble those of a snake, but are far less graceful, owing to
the stiff armour in which the whole body is encased. The food consists
chiefly of snails, the shells of which are crushed, and of mice, but
nothing comes amiss which can be mastered, namely insects, worms, small
lizards, young birds, and vipers. The prey, when caught, is rapidly twisted
round and round, or shaken until it is giddy or stunned, whereupon the
Glass-Snake proceeds to chew it with its powerful jaws, and then to swallow
it in pieces. {539}Although it can bite so well, it never does so when
caught, but resorts to the much more disagreeable defence of twisting
itself around one's hand and arm, and besmearing them with its disgustingly
stinking excrements. Those who have observed Glass-snakes praise their
tameness, and the intelligent way in which they hunt about in search of
their food. They lay eggs under moss and leaves, and the young seem to
require many years to grow up.
[Illustration: FIG. 136.–_Anguis fragilis_ (the Slow-worm). × ½.]
_Anguis_, with only one species, _A. fragilis_, the "Slow-worm" or
"Blind-worm," is devoid of a lateral fold. Limbs are entirely absent. The
whole body is covered with smooth roundish scales, with a substratum of
dermal ossifications. The teeth are curved backwards, fang-shaped, and have
a very faint longitudinal groove on their anterior surface. The ear-opening
is very minute, more or less hidden by surrounding scales. The eyes are
perfectly well developed, provided with movable lids, and it does not speak
well for the power of observation of most people that this creature should
generally be known as the "Blind-worm." The whole skin is shiny, metallic,
quite smooth, brown above, blackish below. But the coloration is subject to
much individual variation. Old specimens are sometimes adorned with blue
specks. The very young are exquisitely beautiful, the upper surface being
silvery white, with a median and two more lateral lines of deep black; the
under parts are black. The iris is yellowish red. Very large specimens
measure more than one {540}foot in length, more than half of which belongs
to the tail. One in the British Museum is 425 mm. = 17 inches long.
The Slow-worm is viviparous, _i.e._ the young are fully developed, and
burst the transparent, soft, yellowish eggs immediately after these are
laid. This takes place in the months of August or September, about one
dozen making a litter. The little creatures are at first about one inch and
a half long, and as thin as an ordinary match. They eat the smallest of
spiders and delicate insects; later on earth-worms, which they bite into
and then suck out before devouring them. When six weeks old and well fed
they are about 3 inches long, but it is at least four or five years before
they are mature. The little ones carefully avoid the hot sunshine, and the
adults are likewise rather partial to the shade, although strictly diurnal.
Their chief food consists of earth-worms and slugs. For the night they
retire under moss, leaves, stones, or into the ground. In the autumn the
Slow-worms dig passages or burrows, which often serve as the
winter-quarters of many specimens, as if there were no other place
available, or rather as if the spot selected were by far the best with
regard to safety, dryness, and warmth.
FAM. 6. HELODERMATIDAE.–Pleurodont, _poisonous_ lizards of North America.
The teeth are fang-like, recurved, with slightly swollen bases, rather
loosely attached to the inner edge of the jaws. Each tooth has a groove on
its anterior and posterior surface, and a series of labial glands which
secrete the poison open near the bases of the teeth of the lower jaw. The
skull has strong postorbital but no postfronto-squamosal arches. The pre-
and post-frontals are in contact, separating the frontal from the orbit;
the premaxillaries are fused into one; the nasals and frontals remain
separate. The limbs are short, but strong and well developed. The tongue is
villose, with an anterior smooth portion, which is bifid and protractile,
resembling the tongue of the Anguidae and of _Aniella_. The skin of the
upper surface is granular, with many irregular bony tubercles, which give
it an ugly warty look. The under parts are covered with flat scales.[161]
_Heloderma_, the only genus, with _H. horridum_ in Mexico and _H.
suspectum_ in New Mexico and Arizona, reaches about 2 feet {541}in length.
The animal, stout, depressed, thick-tailed, looks rather repulsive when it
squats down in its usual lethargic way. The whole skin is blackish brown
and yellow or orange, these two "warning" colours being distributed
unevenly, except on the thick, peculiarly-shaped tail, where they are
arranged in alternate rings. The specific differences are rather imaginary.
The New Mexican form is supposed to be more orange and yellow than black,
with a somewhat smoother skin and with shorter toes and tail.
[Illustration: FIG. 137.–_Heloderma suspectum_ (the Gila Monster). × ⅕.]
The "Gila Monster" inhabits dry localities, spends most of the daytime in
concealment between the roots of trees, and crawls about in the evening in
search of worms, centipedes, frogs, and the eggs of large lizards. Frogs
are probably paralysed or killed by the bite which, although not so
dangerous as that of poisonous snakes, is effective enough to produce
severe symptoms even on man, and a few cases of death of people who had
been bitten are on record. In captivity they are very partial to eggs,
which they break and then lap up. During the dry and hot season they
aestivate.
FAM. 7. LANTHANOTIDAE.–_Lanthanotus borneensis_, of which only two
specimens are known, one in the Vienna Museum, the {542}other in the
Sarawak Museum, was described by Steindachner as the type of a distinct
family, near the Helodermatidae. Boulenger,[162] after examination of the
Sarawak specimen by means of a sciagraph, has come to the conclusion "that
the affinity of _Lanthanotus_ to the Helodermatidae is fully confirmed."
The teeth of _Lanthanotus_ show, however, no traces of grooves;
poison-glands are probably absent, and there are no osteoderms. The skin is
covered with wart-like tubercles, each with a horny, peeled scale. The eyes
are very small, the ears are concealed. The general colour is reddish brown
above, yellowish, with brownish bands, below. Total length about one foot,
a little more than half of which belongs to the roundish tail.
[Illustration: FIG. 138.–A, Ventral, B, dorsal view of the skull of
_Varanus griseus_. × 1. _B.O_, Basi-occipital; _B.S_, basisphenoid; _Col_,
columella auris or stapedial rod; _E.P_, ectopterygoid; _Fr_, frontal;
_Jug_, jugal; _Lac_, lacrymal; _N_, nasals; _Pal_, palatine; _Par_,
parietals; _Pr.f_, prefrontal; _Pt.f_, postfrontal, fused with postorbital;
_Ptg_, pterygoid (endopterygoid); _Q_, quadrate; _Tb_, turbinal; _Vo_,
vomer.]
FAM. 8. VARANIDAE.–_Pleurodont Old-World Lizards, with a long, deeply bifid
and protractile smooth tongue._ They reach a large size, and the neck is
relatively much longer than that of other lizards. The limbs are well
developed. The skin is {543}covered with very small juxtaposed scales and
tubercles above, while the ventral scales are squarish and arranged in
transverse rows. Osteoderms are entirely absent. The tail is very long,
often laterally compressed. The teeth are large and pointed, dilated at the
base. The premaxilla is unpaired and dorsally extends backwards to the
likewise unpaired nasal. There is a pair of small supra-orbital bones,
easily lost during maceration. The orbit is open behind, the jugal being
short and not meeting the postfrontal; the postorbital forms a slender arch
with the supratemporal. The vomers are long and diverge posteriorly. The
palatines, pterygoids, and ectopterygoids enclose on either side an oval
infra-orbital foramen. The Varanidae contain only one genus, _Varanus_,
with nearly thirty species in Africa, Southern Asia, and Australia, but not
in Madagascar.
[Illustration: FIG. 139.–Map showing the distribution of the Varanidae.]
_Varanus._–The name of "Monitor" bestowed upon these creatures has a
curious origin, owing to a ridiculous etymological mistake. The Arabic term
for Lizard is "Ouaran"; this has been wrongly taken to mean warning lizard,
hence the Latin _Monitor_, one of the many synonyms of this genus, e.g.
_Hydrosaurus_ and _Psammosaurus_. Many of the "Monitors" are semi-aquatic,
others inhabit dry, sandy districts, while others are at home in
well-wooded localities. They are all rapacious, taking whatever animals
they can master according to their size, which in some species amounts to 6
or 7 feet.
_V. niloticus_ inhabits the whole of Africa, except the north-western part.
It reaches a length of more than 5 feet. The colour of the adult is
brownish or greenish grey above, with darker reticulations and yellowish
ocellated spots on the back and limbs. The under parts are yellowish with
blackish cross-bands. The ground-colour of the young is black above with
yellow lines on the head and neck, and with yellow spots on the back and
limbs; the tail has black and yellow bars.
_V. salvator_ ranges from Nepal to Ceylon, Cape York, and {544}Southern
China, inclusive of the Malay Islands and the Philippines. This is the
largest species, specimens of 7 feet in length being on record. The general
colour is dark brown or blackish above, with yellow spots or ocelli. The
snout and chin have transverse black lines on a lighter ground. A black
band, bordered with yellow, extends from the eye along the side of the
neck. The under parts are yellow.
Mr. Annandale has favoured me with the following observations:–"_Varanus
salvator_ is common in Lower Siam, where it is equally at home on land, in
water, and among the branches of trees. The eggs are laid in hollow
tree-trunks. When in the water the lizard swims beneath the surface, the
legs being closely applied to the sides, and the tail functioning both as
oar and as rudder. Their food is very varied. In the states of Patalung and
Singora, in which the Siamese practise a form of tree-burial, these great
lizards are accused, probably with justice, of eating the flesh of the
corpses in the aërial coffins. I have disturbed a large Monitor devouring
the body of one of its own species, which had evidently been dead for some
days. Another, which was chased by some men, dropped from its mouth a small
flying squirrel (_Sciuropterus_); a third, which I dissected, had lately
swallowed a small tortoise, the hard shell of which had been broken into
innumerable fragments. The stomachs of several others contained nothing but
dung-beetles, for which Varanus may often be seen hunting, turning over the
dung of elephants and buffaloes with its fore-feet. The Malay name of these
lizards is Biawak."
According to Mason and Theobald[163] all the Varanidae and their eggs are
highly esteemed for food, and are sought for in hollow trees with the aid
of dogs. If not wanted at once, the wretched creature has its fore-feet
bent over its back, a few of its toes are broken and the sinews drawn out
and tied into a knot, rendering the animal helpless. The Karens, who are
extravagantly fond of the flesh, steal up the tree with a noose at the end
of a bamboo, and often noose them while leaping for the water, or catch
them in a boat which is brought under the tree. The head, the natives say,
is venomous, and they discard it altogether, but the flesh of the other
parts, which smells most odiously, is deemed preferable to that of fowls.
{545}Sir J. G. Tennent[164] gives the following account of _V. salvator_:–
"The 'Kabara-goya' of the Singhalese is partial to marshy ground, and when
disturbed upon land will take refuge in the nearest water. From the
somewhat eruptive appearance of the yellow blotches on its scales, a
closely allied species, similarly spotted, obtained the name of _Monitor
exanthematicus_, and it is curious that the native appellation of this one,
_Kabara_, is suggestive of the same idea. The Singhalese, on a strictly
homoeopathic principle, believe that its fat, externally applied, is a cure
for cutaneous disorders, but that taken inwardly it is poisonous. The
skilfulness of the Singhalese in their preparation of poisons and their
addiction to using them are unfortunately notorious traits in the character
of the rural population. Amongst these preparations the one which above all
others excites the utmost dread, from the number of murders attributed to
its agency, is the potent _kabara-tel_, a term which Europeans sometimes
corrupt into _cobra-tel_, implying that the venom is obtained from the
hooded-snake; whereas it professes to be extracted from the Kabara-goya.
"In the preparation of this mysterious compound, the unfortunate
Kabara-goya is forced to take a painfully prominent part. The receipt, as
written down by a Kandyan, was sent to me from Kornegalle by Mr. Morris,
the civil officer of that district; and in dramatic arrangement it far
outdoes the cauldron of Macbeth's witches. The ingredients are extracted
from venomous snakes by making incisions in the head of these reptiles and
suspending them over a basin to collect the poison as it flows. To this,
arsenic and other drugs are added, and the whole is boiled in a human
skull, with the aid of three Kabara-goyas, which are tied on three sides of
the fire, with their heads directed towards it, and tormented by whips to
make them hiss so that the fire may blaze. The froth from their lips is
then added to the boiling mixture, and so soon as an oily scum rises to the
surface, the kabara-tel is complete. Before commencing the operation of
preparing the poison, a cock has to be sacrificed to the demons.
"This ugly lizard is itself regarded with such aversion by the Singhalese
that if one enter a house or walk over the roof, it is regarded as an omen
of ill-fortune, sickness, or death; and in {546}order to avert the evil, a
priest is employed to go through a rhythmical incantation."
Captain Robinson, renowned as a hunter of tigers on foot in the old days of
muzzle-loading rifles, has told me the following unique use to which these
large lizards are put by ingenious thieves in India. In order to be able to
get over a wall too high for climbing without assistance, the thief
provides himself with a strong lizard, ties a rope round its waist and lets
the animal go, when it at once scales the mud wall by its strong and sharp
claws, and jumps down on the other side. The weight of the lizard, which,
moreover, holds vigorously on to the ground, and the friction of the rope
on the top of the wall, are sufficient to help the man over!
[Illustration: FIG. 140.–_Varanus salvator_ swallowing a Fowl's egg. × ⅛.]
It is a sight, never failing in its attraction to the visitors of the
Zoological Gardens in London, to see one of the big Monitors fed with an
egg. The lizard knows the treat well that is in store for it. It raises
itself up high in expectation, then examines the egg with the long tongue,
takes it up gingerly and swallows it entire, crushing it by the contraction
of the muscles of its gullet. On one occasion it was given a rotten egg
which burst in its mouth, and the lizard refused for a long time to take
another.
_V. gouldi_ is common in Australia and in New Guinea. It reaches a length
of about 4 feet. Its colour is brown above {547}with yellow spots on the
back and limbs, and with yellow rings on the tail. Two yellow streaks
separated by a black band extend from the temples along the side of the
neck. The under parts are yellowish, sometimes with black spots.
FAM. 9. XANTUSIIDAE.–Three Californian, or West-Indian genera, with less
than half-a-dozen species. _Pleurodont with a short tongue and with the
supratemporal fossa roofed over by bone._ The tongue is scarcely
extensible, with oblique overlapping folds which converge towards the
median line, and with scale-like imbricate papillae towards the tip. The
skull possesses complete postorbital and postfronto-squamosal arches, the
latter meeting the parietals and roofing over the supratemporal fossa. The
palatines are in contact with each other, and there are no infra-orbital
fossae. There are no osteoderms; the body is covered above with small
granular scales, below with larger scales. The eyes are devoid of movable
lids. The tympanum is exposed. Femoral pores are present. Limbs and tail
well developed. _Xantusia_ and _Lepidophyma_.
FAM. 10. TEJIDAE.–American Lizards with a long and bifid tongue. The
greater portion of the tongue is covered with scale-like papillae; the
anterior forked and pointed ends are smooth. The teeth are solid and
implanted almost upon the edge of the jaw, being therefore intermediate
between the acrodont and pleurodont condition. The shape of the posterior
teeth shows several modifications; they are conical or tricuspid, or
molar-like in the adult Tejus; in _Dracaena_ they are transformed into
large, oval crushers. The palatines are in contact anteriorly. The
infra-orbital fossae are surrounded by the palatine, pterygoid, and
ectopterygoid bones, the maxillary being excluded from the fossa, as in
_Varanus_ (see Fig. 138, p. 542). The skull has no supra-temporal arch.
Osteoderms are absent; the body is covered with small scales, or the skin
is simply granular above; the under surface is covered with larger scales,
generally arranged in transverse rows.
This large family, which comprises nearly forty genera with more than a
hundred species, exhibits great diversity of form. Some are inhabitants of
forests and are arboreal, while others are strictly terrestrial, preferring
hot and sandy plains, or they dwell below the surface and are transformed
into almost limbless and blind-worm-shaped creatures. The range of the
family extends over the whole of the South American continent, over the
West {548}Indian Islands, and through Central America into the warmer parts
of the United States.
_Tupinambis_ ("Teju").–The skin of the back is smooth, covered with small
scales; with large scales on the top of the head. The skin on the neck is
generally thrown into two irregular transverse folds. The long and narrow
tongue is capable of being telescoped into a sheath at its base. The
lateral teeth are compressed and tricuspid in the young, but the later
generations of teeth have obtuse crowns in the adult. _T. teguixin_ is the
largest member of the whole family; it reaches a length of a yard, most of
which, however, belongs to the tail. The general colour is bluish black,
with pale or whitish-yellow spots on the back, flanks, and tail, combining
into more or less transversely arranged bands. The limbs are black, with
many and tiny yellow dots. The ground-colour of the under parts is reddish
yellow, with irregular black bars. This species inhabits the greater part
of South America, east of the Andes, from Uruguay to the West Indies. _T.
nigropunctatus_ is confined to the Continent, and lacks the dark
cross-bands on the belly, which is uniformly yellowish or speckled with
black.
[Illustration: FIG. 141.–_Tupinambis nigropunctatus._ × ⅙.]
{549}The "Tejus" frequent forests and plantations, and are carnivorous.
Their strength and swiftness enable them to catch all kinds of animals,
from insects and worms to frogs, snakes, mice, and birds. As they take
chickens and eggs from the farms they are considered noxious, and they are
frequently hunted down with dogs for the sake of their flesh, which is
regarded as good to eat. They defend themselves with lashing strokes of
their long tail and with their powerful jaws. They retire into burrows, and
they deposit their hard-shelled eggs in the ground. In captivity they can
easily be kept on meat.
_Dracaena guianensis_ of the Guianas and the basin of the Amazon has the
lateral teeth transformed into regular large molars, with broad and rounded
crowns. The tail is strongly compressed, with a double, denticulated keel.
It seems to be semi-aquatic, and, to judge from the teeth, herbivorous.
_Ameiva_ and _Cnemidophorus_, with many species chiefly in tropical
America, have laterally compressed bi- or tri-cuspid teeth. The skin forms
a double fold on the neck, and is covered on the upper surface of the body
with very small scales; those on the ventral surface are large, and
arranged in regular rows. Most of the species are small, under one foot in
length, and are extremely pretty, very active, timid, and mainly
insectivorous.
_C. sexlineatus_ is one of the few species of _Cnemidophorus_ which
inhabits the southern half of North America. Like all its relations it has
the appearance of an ordinary lizard (_Lacerta_). The head is dark brown. A
purple or brownish band extends over the back and tail, bordered on either
side with three golden-yellow longitudinal lines. The flanks are brown, the
under parts bluish white. The iris is golden, and the inner margins of the
lids are bordered with a narrow band of bright yellow. This species is a
very fast runner, and frequents dry and sandy places. Its total length
amounts to about 10 inches.
FAM. 11. LACERTIDAE.–_Pleurodont Old-World Lizards, without osteoderms on
the body, and with the supratemporal regions roofed over by osteoderms._
The limbs are always well developed, and have five fingers and five toes,
always provided with sharp claws. The skin covering the head forms large
shields, mixed with small scales; most of which, especially the shields,
contain dermal ossifications. These frequently fuse with the underlying
bones of the top of the skull.
{550}[Illustration: FIG. 142.–Skull and lower jaw of _Lacerta viridis_. A,
Dorsal view; B, ventral view; C, from the left side; D, right half of the
lower jaw, from the inner side, with some of the pleurodont teeth. _E.P_,
Ectopterygoid; _F_, _Fr_, frontal; _jug_, jugal; _Lac_, lacrymal; _Max_,
maxillary; _N_, _Na_, nasal; _N_{1}_, in B, inner narial opening; _Pal_,
palatine; _Par_, parietal; _Pmx_, premaxillary; _Pr.f_, prefrontal; _Pt.f_,
postorbital; _Pt.f_{2}_, postfrontal; _Ptg_, pterygoid; _Q_, quadrate;
_S.ang_, supra-angular; _Sq_, squamosal; _Vo_, vomer.]
The latter is always well marked off from the neck. The postorbital arch is
complete. The temporal region is completely roofed over by bones dorsally,
chiefly owing to the size of the postfrontal (Fig. 142, _pt.f_{2}_) which
fills the space between the parietal and the squamoso-postorbital bridge,
thus abolishing the supra-temporal fossa. The squamosal is very small,
placed {551}between the postfrontal (_pt.f_{2}_), the lateral occipital and
the supratemporal. The large jugal and the quadrate are not connected with
each other. The columella cranii is well developed. The infra-orbital
fossae are surrounded by the palatines, pterygoids, ectopterygoids, and
maxillaries. The palatines and pterygoids remain separated in the middle
line. The pterygoids frequently carry little teeth. The other teeth are
typically pleurodont, hollow, slightly curved, and bi- or tri-cuspid.
The skin covering the body, the legs, and the tail is devoid of osteoderms.
The scales on the dorsal surface vary much in size, from large, strongly
keeled scales to tiny granulations. Those of the ventral surface are large,
broader than long, and are frequently arranged in regular transverse and
longitudinal rows. The tail, generally long and pointed, is very brittle.
All the sense-organs are well developed. The tympanum is exposed. The
tongue is deeply bifurcated, narrow, flat, and covered with scale-like
papillae.
Various Lacertidae, especially some of those genera which live and dig in
the sand, have a transparent disc in the middle of the lower eyelid, so
that they can see while the eye itself is protected. This is for instance
the case in some specimens of the Indian and African _Eremias_. In the
Indian genus _Cabrita_ the transparent disc is very large, and in
_Ophiops_, which inhabits sandy stretches from North Africa to India, the
lower eyelid is fused with the rim of the much-reduced upper lid, and forms
a large transparent window.
The Lacertidae or True Lizards comprise nearly twenty genera, with about
one hundred species, and are typical of the Old World, being found in
Europe, Asia, and Africa, but not in Madagascar nor in the Australian
region. They are most abundant in Africa. Their northern limit coincides
fairly closely with the limit of the permanently frozen under-ground. This
is indicated in the map (Fig. 143) by the dotted line. All the Lacertidae
live upon animal food, chiefly insects, and after them worms and snails;
but the larger lizards take what they can master, frequently other lizards,
and even younger members of their own kind. Many of them love sugar, which
they lick, and all require water. They are all terrestrial, preferring,
according to their kind, such localities as yield them their particular
food.
{552}[Illustration: FIG. 143.–Map showing the distribution of the
Lacertidae.]
Sunshine and warmth make a marvellous change in the same individual, which
on dull, rainy, or cold days lies in its hole, or shows only sluggish
movements. Their sense of locality is great, or rather each individual
inhabits one place, of which it knows every nook and corner, cranny, tree,
and bush. It has its favourite hole to sleep in, a stone, the branch of a
tree, or a wall to bask upon, and when disturbed or chased it makes with
unerring swiftness for a safe spot to retire into. The same lizard, when
once driven away from its own locality, seems to lose all its presence of
mind, flounders about, and is comparatively easily caught. Most lizards are
extremely curious, although shy, and this state of their mind can be made
use of by those who want to catch them without injury, and above all
without getting the animal minus the brittle tail. This safe way of
catching lizards consists in taking a thin rod with a running noose of
thread at the end, in drawing the latter over the lizard's head, and then
raising it. The little creature does not mind the rod in the least; on the
contrary, it watches it carefully, and often makes for the thread. The boys
in Southern Italy have improved upon and simplified this mode of catching
lizards by bending the end of a wisp of grass into a noose, and covering
the latter over with a thin film of saliva. The shiny film, like a
soap-bubble, is sure to excite the curiosity of the creature. The late
Professor Eimer[165] refers to this practice {553}as carried out by the
children of two thousand years ago, and he sagaciously explains that the
beautiful statue of the so-called Apollo Sauroctonos represents a boy who
is in the act of noosing the little lizard on the tree.
_Lacerta._–A row of enlarged scales forms a distinct collar across the
ventral half of the neck, in front of the chest. The scales on the back are
much smaller than those on the tail, which is long, round, and pointed. The
digits have smooth, tubercular lamellae on the under surface. Femoral pores
are well marked. This genus, with about twenty species, ranges through
Europe, Northern and Western Asia, and Africa north of the Equator.
_L. vivipara_, the Common English Lizard, has a very wide range, through
Northern and Central Europe and Siberia to the Amoor country and the Island
of Saghalien. It occurs throughout Great Britain, even in Ireland, where it
is the only species of reptile, occurring, for instance, in the County of
Meath and in the south-eastern counties, _e.g._ Waterford. It does not
occur south of the Pyrenees or south of the Alps. The supra-ocular and the
supraciliary scales are in contact with each other, not being separated by
a series of little granules. Normally there is a single postnasal and a
single anterior loreal shield. The ventral scales are arranged in six or
eight longitudinal series, of which the second series on each side from the
median ventral line is the largest. The coloration of this species is
subject to much variation. The general colour of the adult is brown or
reddish above, with small darker and lighter spots; many specimens have a
blackish vertebral streak and a dark lateral band edged with yellow. The
under parts are orange to red in the male, with conspicuous black spots;
yellow or pale orange in the female, either without or with scanty black
spots. The newly-born specimens are almost black. The males are slightly
smaller than the females; males of a total length of 6 inches, and females
7 inches long, may be considered rather large specimens.
This lizard is, as the specific name implies, viviparous, i.e. the six to
twelve young burst the eggs immediately after they have been laid;
sometimes the mother has to retard the laying, in which case the young are
born free. The female does not make a nest, but simply deposits her
offspring on the ground and leaves the young to their fate. For the first
few days the little ones, which scarcely measure three-quarters of an inch
in {554}length, remain almost motionless between leaves or in cracks of the
ground, and they do not take any food. They grow, however, quickly, living
upon the remains of the yolk which has slipped into their body. Their first
food consists of Aphides and similar tiny insects.
The Common Lizard prefers moist localities and is very hardy. It extends
northwards to Archangel, and in the Alps it ascends to nearly 10,000 feet
above the level of the sea. However, on the approach of the cold season, in
the month of October, it withdraws into its winter quarters, frequently in
company with many of its own kind.
_L. agilis_, the Sand-Lizard, has nearly the same wide range as _L.
vivipara_, except that it does not go so far north and does not extend
eastwards beyond Central Siberia. It is absent in Ireland and Scotland,
while in England it is restricted to the southern half.
The characters which distinguish the Sand-Lizard from _L. vivipara_ are
few, although the majority of the specimens of either kind are very
distinct in their coloration, and _L. agilis_ is strictly oviparous,
depositing its eggs in the ground, under leaves, in heaps of weeds and
similar places. The Sand-Lizard has usually a single postnasal and two
superposed anterior loreals, the three shields forming a triangle. The
temples are covered with flat scales, two or three of which are enlarged
and in contact with the parietals, but there is no tympanic scale.
The coloration is subject to much variation, local as well as individual.
As a rule the Sand-Lizard gives the impression of being striped
longitudinally, the striation being caused by rows of dark and white spots
and patches along the sides of the back, flanks, and tail. In the male a
more or less pronounced green, in the female brown and grey are the
prevailing ground-colours. A typically coloured male during the breeding
season is grass-green on the sides and suffused with green on the yellow
under parts; the sides are dotted with black, with whitish eye-spots. The
under parts are spotted with black. The adult female is brown or grey
above, with large dark brown, white-centred spots, which are arranged in
three rows on each side. The under parts are cream-coloured, with or
without black specks. The young are grey-brown above with white,
black-edged spots; the under parts are whitish. Total length of the adult
up to 8 inches. {555}The male is a little smaller than the female but has a
relatively longer tail, a little less than half the total length.
The Sand-Lizard is easily kept in captivity, and lives for years if allowed
a variety of food and proper places to hibernate in. It pairs in the
spring, in England in May or June; the white, parchment-like eggs,
numbering five to eight, are hatched in the following July or August.
_L. viridis_, the Green Lizard, inhabits Southern and Middle Europe and
South-Western Asia. The general colour of this beautiful lizard is
emerald-green above, changing into greenish yellow on the flanks and into
yellow on the belly. The throat, especially in the males during the
breeding season, is blue. The upper parts are frequently speckled with
black. The young are brown or green above with one or two yellowish lateral
stripes, which persist in some adult females. There are usually two
superposed postnasal shields. The semilunar collar on the neck is well
pronounced, and there is usually a distinct gular fold. The tail is often
very long, especially in the males, sometimes nearly three-quarters of the
total length, which in very large males reaches 16 or 17 inches. The
females do not quite reach this length.
The Green or Emerald-Lizard prefers rocky localities, from the sea-level,
as for instance in Jersey, up to a height of several thousand feet. It is
extremely swift and can climb trees, which it sometimes resorts to when
chased. When hard pressed it takes tremendous leaps down to the ground,
marvellously enough without injury to body or tail, which latter is
otherwise very brittle. They pair in the spring or early summer after much
fighting between the males; the eggs, to the number of about ten, are
whitish and are deposited a month later. The young are hatched after
another four weeks.
This beautiful lizard does not keep well in captivity, although it becomes
very tame; it eats meal-worms, snails, earth-worms, and insects, especially
butterflies, but it sickens after the first winter even if it has been
allowed to hibernate.
In Portugal and Spain _L. viridis_ is represented by a slightly different
kind, _L. schreiberi_, the chief interest of which lies in the fact that it
approaches _L. ocellata_ in several respects. The occipital shield is large
and is usually broader than the interparietal. The dorsal scales are
smaller, and there are eight {556}well-developed rows of ventral scales.
Instead of being uniformly green, the upper parts are usually spotted and
vermiculated with black; sometimes, especially in the females, the black
spots have a white ocellus in the centre. The under parts are yellowish,
with or without black spots. The throat is blue. The young look very
different. They are olive-brown above with large yellow, or bluish-white,
black-edged ocelli on the side of the head and body.
Other forms, perhaps of sub-specific rank, approaching _L. ocellata_, occur
in the Balkan Peninsula, where, for instance in Dalmatia, the typical _L.
viridis_ attains its most beautiful development.
[Illustration: FIG. 144.–_Lacerta ocellata_ (the Eyed Lizard). × ⅓.]
_L. ocellata_, the Eyed Lizard, inhabits Spain and Portugal, extending
northwards into the South of France and into the Riviera, southwards into
Morocco and Algeria; these southern forms (_L. pater_ and _L. tangitana_)
approach _L. viridis_. The Eyed Lizard is green or dark olive above, with
black or yellowish dots, which are sometimes combined into a kind of
network pattern. The under parts are uniformly greenish yellow. The sides
of the body are adorned with about two dozen blue, black-edged spots or
"eyes." The intensity of the blue and the depth of the green ground-colour
vary much according to sex, time of the year, and state of health. Males
during the breeding season are most beautiful and brilliant. The occipital
shield is broad; there are two superposed nasal but no tympanic shields.
The supraoculars are separated from the supraciliaries by a series of
granules. The collar is well marked, but not the gular fold. {557}The
dorsal scales are minute and granular; the ventral shields are arranged in
eight or ten longitudinal rows.
The "Eyed Lizard" reaches a considerable size, especially the males, which
develop a very strong and thick head, and are much more robust and powerful
than the more slender females. Old males reach a length of 2 feet,
two-thirds of which length belong to the tail; but the latter varies much,
even if it has never been broken and renewed.
The Eyed Lizard keeps extremely well in captivity, and in this respect is
unlike the Green Lizard. A case has been recorded of its living thirteen
years. This species is very intelligent. Although at first ferociously wild
and biting furiously, these lizards soon become tame and take food
regularly. One of my own, a half-grown male from Northern Spain, about one
foot in length, made its home in a little niche of the greenhouse-wall,
whence it emerged regularly to take the offered food from my hand. It soon
knew the whole place thoroughly, making use of the creepers whilst scaling
up to its retreat, jumping over certain gaps, descending to the ground at
certain spots, basking on certain stones, invariably in the same methodical
way. In the month of October it retires into the ground on the coolest side
of the greenhouse, and although the latter is well warmed, the lizard
remains invisible until the next February or March, when on some fine day
it is rediscovered basking upon exactly the same stone where it had been
seen five months before. The only drawback in connexion with keeping this
kind of lizard in company with other creatures is their voraciousness;
since large, fully adult specimens attack and eat any other small lizard,
slow-worm, or snake they can find. They also take mice. The eggs are often
deposited in hollow trees.
_L. muralis_, the Wall-Lizard, is very common in Southern Europe, Asia
Minor, and Northern Africa. Northward it extends into Belgium and into
South Germany. In the Iberian Peninsula it ascends up to 5000 or 6000 feet
above the level of the sea. This graceful little creature, with an average
length of 6 to 8 inches, is easily recognised by the series of granules
between the supraocular and supraciliary scales and usually by having only
six rows of ventral scales. The great variety in coloration has given rise
to the establishment of many races, varieties, and sub-species. In the
typical forms the upper parts are brown or {558}greyish, with blackish
spots or streaks, sometimes with a bronzy greenish sheen. The under parts
are white, yellow, pink, or red, either uniform or, especially in the
males, with large black spots. The lateral rows of ventral shields are
frequently blue. The colour-varieties are almost endless. One of the most
noteworthy is that described as var. _coerulea_ by Eimer; this, confined to
the Faraglione Rocks near Cápri, is blackish above, like the rock, and
sapphire-blue below. Similarly coloured specimens, var. _lilfordi_, occur
on some of the rocky islets of the Balearic Isles.
The Wall-Lizard deserves its name, since in the Mediterranean countries
there is scarcely a wall on which these active lizards do not bask or run
up and down, often head downwards, in search of insects. They are
oviparous. The hibernation is short and not very deep, since these lizards
can sometimes be seen basking on sunny winter days before their regular
appearance in the early spring.
_Psammodromus_, with a few species in South-Western Europe, notably in the
Iberian Peninsula and in North-Western Africa, has no distinct semilunar
collar, but has a short fold in front of each arm. The back is covered with
large, rhombic, strongly keeled and imbricating scales. The lateral scales
pass gradually into the ventrals, which are smooth and arranged in six
longitudinal rows.
_P. hispanicus_ is bronzy brown above, with small black and white specks,
and with one or two longitudinal streaks on each side. The under parts are
white. Total length about 5 inches. Although also found inland, this
species prefers sandy dunes, studded with prickly and scanty vegetation. It
runs very fast and digs itself rapidly into the sand when pursued. When
caught it either utters a faint cry like "tsi-tsi," or it feigns death. The
pairing takes place in June; half-a-dozen eggs are laid about eighteen days
later, deeply imbedded in the warm sand, and they are hatched in eight
weeks. The eggs are said to grow[166] after they have been laid from 13 by
7 mm. to 17-20 by 10-11 mm. The newly hatched little creatures measure
about 2 inches in length, more than half of which belongs to the tail.
_P._ (_Tropidosaura_) _algirus_ has the same range as _P. hispanicus_, but
grows to 10 inches in length, and is much more {559}beautifully coloured.
The upper parts are bronzy brown with one or two golden, dark-edged,
lateral streaks; the under parts are whitish; the male has one or more
blue-eyed spots above each shoulder.
_Acanthodactylus_ is distinguished by the laterally fringed digits. This
genus ranges throughout Northern Africa to the Punjab. One species, _A.
vulgaris_, extends into Spain and Portugal. The dorsal scales are small and
almost smooth, but those on the tail are strongly keeled; the ventrals are
much broader than long, and are arranged in eight to ten rows. The fringes
on the digits are but feebly developed in the shape of lateral
denticulations. The adults are grey-brown with faint longitudinal stripes,
and with more conspicuous black and pale spots; in the breeding season
larger blue-eyed spots appear on the sides near the limbs. The tail is
often pink, especially on the under surface. Total length about 7 inches.
FAM. 12. GERRHOSAURIDAE.–Pleurodont African Lacertidae with osteoderms on
the head and body.
This family is intermediate between the Lacertidae and the Scincidae. The
tongue is constructed like that of the Lacertidae, but is only feebly
nicked anteriorly. Dermal ossifications roof over the temporal region, and
femoral pores are present. On the other hand, the osteoderms, which cover
the whole body, are in their structure and arrangement typically Scincoid.
The tail is long and fragile. A lateral fold is usually present. The limbs
are sometimes reduced to useless stumps. The few genera and species of this
family are strictly confined to the African sub-region, being found in the
whole of Africa south of the Sahara, and in Madagascar.
_Gerrhosaurus_, with a strongly developed lateral fold and complete limbs,
occurs in Africa. _G. flavigularis_, of South Africa, has a total length
about one foot.
_Tetradactylus_, of South Africa, has also a strong lateral fold, but the
limbs are either very short and pentadactyle (_T. seps_), or tetradactyle,
or they are minute pointed stumps, as in _T. africanus_.
FAM. 13. SCINCIDAE.–Pleurodont lizards with strongly developed osteoderms
on head and body, with very feebly nicked, scaly tongue, with complete
cranial arches, and with separated premaxillaries.
{560}The temporal region is covered over, as in the Lacertidae, with
strongly developed, bony, dermal ossifications. Similar osteoderms underlie
the scales which cover the body and tail. The tongue is relatively short,
not forked behind, and but very feebly nicked at the tip; it is covered
with scale-like papillae. Femoral pores are absent.
All the Skinks prefer dry, sandy ground, in which they not only burrow, but
move quickly about, either for protection or in search of their animal
food. In connexion with this sand-loving and at least temporary
subterranean life stands the frequent reduction of the limbs. Every stage
from the fully developed and functional pentadactyle limb to complete
absence of limbs is represented. There are species within the same genus
with five, four, three, or two fingers or toes. There are Skinks without
fore-limbs, but with vestigial hind-limbs, and _vice versa_. The
interesting point is that these reductions do not indicate relationship
within the family, but have happened independently. They are impressive
illustrations of convergent retrogressive evolution.
_Ablepharus_, widely distributed in the Old World, has the lower eyelid
transformed into a transparent cover, which is fused with the rim of the
reduced upper lid, exactly as in the Lacertine genus _Ophiops_.
All the Scincidae seem to be viviparous, some of them, e.g. _Trachysaurus_,
in the strict sense of the word, since the hard or parchment-like egg-shell
has been dispensed with.
The family contains about four hundred species, which have been arranged in
nearly thirty genera, many of them on fanciful grounds. The family is
cosmopolitan, but reaches its greatest diversity in numbers and forms in
the tropical parts of the Old World, especially in the Australian region,
inclusive of the islands of the Pacific. America, notably South America,
has the smallest number.
_Trachysaurus_, with one species, _T. rugosus_, inhabits the whole of the
Australian continent. It is easily recognised by the large and rough
scales, and the short and broad stump-like tail. It is dark brown above
with yellowish irregular markings; the under parts are yellowish, marked
with brown. Embryos of this species have yellow transverse bands on the
back, but these often fade away before birth. The creature is strictly
{561}viviparous, the egg-membrane being very thin, and the two or three
embryos are ripened in uterus-like dilatations of the oviducts. The period
of gestation is about three months, and the birth takes place, in South
Australia, about April. According to Fischer[167] this species, which is
often in the market, is easily kept. It requires warmth, sand and stones
for basking, and water, in which it soaks itself preparatory to the
shedding of the skin, which takes place half-a-dozen times in the year, and
is a slow process, requiring eight to ten days. The food consists chiefly
of worms, lizards, and snakes, but meat, cabbage, and lettuce are also
taken. The total length is about one foot.
[Illustration: FIG. 145.–_Trachysaurus rugosus._ × ⅓.]
_Cyclodus_ s. _Tiliqua_, of Australia, Tasmania, and the Malay Islands, has
stout lateral teeth with spherical crowns. The imbricating, cycloid scales
of the body and the rather short but pointed tail are quite smooth and
shiny. _C. gigas_, of New Guinea and the Moluccas, reaches a length of
nearly 2 feet. The general colour is brownish yellow, with broad, dark
bands across the body and tail.
_Scincus_, of North Africa, Arabia, Persia, and Sindh, has pentadactyle
limbs, with laterally serrated digits. The eyelids are well developed, but
the ear is hidden under scaly flaps. _S. officinalis_, of the Sahara and of
Egypt, grows to about 8 inches in length. The snout is peculiarly shaped,
cuneiform. The eyes are very small. The scales of the body are perfectly
smooth; the sides of the belly are somewhat angular. The {562}whole shape
of the creature, the scales, and the digits are adapted to burrowing and
moving quickly through the loose sand. The general colour is yellowish or
brownish above, each scale with small brown and whitish spots; the under
parts are uniform whitish. The young are quite beautiful, being uniform
pale salmon-coloured above, silvery white below. When a little older,
yellow spots appear on the flanks and grey bands across the back. These
Skinks live in the absolutely dry reddish-yellow sand of the desert, in
which they may almost be said to swim about, so swift and easy are their
movements. They live on insects, while in their turn they are eaten by
snakes, and above all by the _Varanus_ lizards.
[Illustration: FIG. 146.–_Cyclodus gigas._ × ¼.]
Of _Mabuia_ with about forty species, in the whole of Africa, Southern
Asia, and in Tropical America, we mention only _M._ (_Euprepes_) _vittata_,
on account of its partly semi-aquatic life, a very rare condition among
Scincidae. This creature, about 7 inches long when full grown, frequents
damp localities in Tunis and Algeria, where the French call it "Poisson de
sable." It often sits on the floating leaves of _Nymphaea alba_, and dives
into the water in order to escape. Its proper element is, however, the
sand, and for the night it retires under stones. The general colour is
olive brown with a lighter vertebral band and two narrow whitish lines on
each side, sometimes edged with black. The under parts are yellowish or
greenish white.
_Chalcides_ s. _Seps_ s. _Gongylus_, of the Mediterranean countries
{563}also occurs in South-Western Asia. The lower eyelid has a transparent
disc. The body is much elongated, and is covered with smooth shiny scales.
The limbs are very short, or reduced to mere vestiges.
_Ch. ocellatus_, of the Southern Mediterranean countries, occurring also in
Malta and Sardinia, reaches about 10 inches in length. The snout is
conical, the ear-opening a small slit or hole. The limbs have five fingers
and toes. The under parts are uniform silvery white, but the colour of the
upper parts is very variable, mostly olive brown with black spots and
irregular cross-bars, or with dark and light spots; sometimes uniform
bronzy brown with a light upper and a black lateral band. This Skink seems
to have no fixed abode, but digs itself into the sand wherever it wants to
hide. The skin is not shed in flakes, but, as in most Skinks, it peels off
by a process of gradual desquamation. Fischer's specimens paired towards
the end of December. The gestation lasted 56 days, when nine young were
born, which measured about 75 mm. or 3 inches; when three weeks old they
had increased to nearly double this length.
_Ch. lineatus_, of Spain and Portugal, and of the South of France, like
_Ch. tridactylus_ of Italy and North-West Africa, has only three fingers
and toes. The fore-limbs are only about one quarter of an inch in length in
large specimens of 10 inches total length; the hind-limbs are a little
longer. The general colour is bronzy olive or brown above, in the former
species with nine or eleven darker longitudinal streaks; uniform, and with
an even number of streaks in the latter species. _Ch. bedriagae_, of Spain
and Portugal, has mostly five fingers and toes, and the limbs are
relatively longer in this smaller species; but it is a question if these
and other species of this genus are not to a great extent simply individual
variations, since the reduction of the limbs and toes seems to be a very
recent feature. _Ch. guentheri_, of Palestine, otherwise in every respect
like _Ch. tridactylus_, but reaching a length of more than 14 inches, has
the limbs reduced to tiny conical stumps without a trace of separate
digits.
I have caught _Seps_ accidentally under stones or pieces of bark in sandy
districts. On the western coast of Galicia and Portugal, close to the sea,
they frequent the gorse-bushes, on which they can be seen basking, provided
they are approached {564}stealthily. They disappear on the slightest alarm,
almost swimming, as it were, with great agility through the prickly cover,
and then hiding and wriggling through the loose sand between the roots.
The following five "families" are composed of degraded forms of various
descent. Most of them lead a burrowing, subterranean life, in adaptation to
which the body has become snake-shaped or worm-like. The fore-limbs are
entirely absent, except in _Chirotes_; the hind-limbs are absent, or
reduced to small flaps; the girdles are reduced correspondingly. The skull
is devoid of postorbital, postfronto-squamosal, supratemporal, and jugal
arches. The quadrate bone is mostly immovable. The eyes and ears are
concealed, except in the Pygopodidae.
FAM. 14. ANELYTROPIDAE.–An artificial assembly of a few degraded Scincoids.
The worm-shaped, limbless body is devoid of osteoderms. The tongue is
short, slightly nicked anteriorly, and covered with imbricating papillae.
Columellae cranii are present. _Anelytropsis papillosus_ in Mexico.
_Typhlosaurus_ and _Feylinia_ in South and West Africa.
FAM. 15. DIBAMIDAE, consisting of the genus _Dibamus_, with _D.
novae-guineae_, in New Guinea, the Moluccas, Celebes, and the Nicobar
Islands. The tongue is arrow-shaped, undivided in front, covered with
curved papillae. Columellae cranii are absent. The vermiform body is
covered with cycloid imbricating scales without osteoderms. The limbs and
even their arches are absent, but in the males the hind-limbs are
represented by a pair of flaps. Total length of the animal about 6 inches.
FAM. 16. ANIELLIDAE.–The genus _Aniella_ comprises a few small worm- or
snake-shaped species in California, which seem to be degraded forms of
Anguidae. The eyes and ears are concealed, limbs are entirely absent, the
body and tail are covered with soft, imbricating, more or less hexagonal
scales. The tongue is villose, smooth, and bifid anteriorly. The teeth are
relatively large, few in numbers, recurved, with short swollen bases. The
skull, by reduction, approaches the Ophidian type; there is no columella
cranii, the postorbital arch is ligamentous, the premaxillary is single,
the nasals and frontals remain separate, the pre- and post-orbitals are in
contact with each other, excluding the frontal from the orbit.
_A. pulchra._–Silvery, the scales edged with brown; back and {565}tail with
a narrow, brown, median line. Total length, 7 to 8 inches.
FAM. 17. AMPHISBAENIDAE.–Worm-shaped lizards with the soft skin forming
numerous rings, each of which is divided into many little squares, the
vestiges of scales which are otherwise restricted to the head. The eyes and
ears are concealed. Limbs are absent except in _Chirotes_, which has short
four-clawed fore-limbs. The pectoral arch, and still more so the pelvic
arch, are reduced to minute vestiges. The tail is very short. The skull is
small, compact, and strongly ossified, in adaptation to the burrowing life,
and is devoid of postorbital and postfronto-squamosal arches and of
columellae. The teeth are either acrodont or pleurodont. The tongue is
slightly elongated, covered with scale-like papillae, and bifurcates into
two long and narrow smooth points.
[Illustration: FIG. 147.–Map showing the distribution of Amphisbaenidae.]
The Amphisbaenas lead an entirely subterranean, burrowing life, like
earth-worms. They are frequently found in ants' nests or in manure-heaps.
Their progression is very worm-like, their annulated soft skin enabling
them to make almost peristaltic motions and to move backwards as well as
forwards. They crawl in a straight line, with slight vertical waves, not,
like other limbless lizards or snakes, by lateral undulations. The food
consists of worms and small insects. About one dozen genera with more than
sixty species are known, most of which inhabit the warmer parts of America,
the West Indies, and Africa. Four inhabit Mediterranean countries.
{566}If the tongue and the dentition be taken as indications of
relationship, the Amphisbaenidae may perhaps be considered as degraded
descendants of Iguanidae, a family which contains various limbless,
burrowing, worm-shaped forms. But it is also possible that the
Amphisbaenidae are not a natural group. This consideration applies with
most force to the genera _Amphisbaena_ and _Anops_, the various species of
which occur in America and in Africa.
_Chirotes canaliculatus_, the only species of the genus, is the only
Amphisbaenid which still possesses fore-limbs. These are short, stout,
placed close behind the head, and are provided with four-clawed digits.
This species occurs in Mexico and California, is brownish or
flesh-coloured, and reaches a length of about 8 inches.
_Amphisbaena_, with nearly thirty species, in Tropical America and Africa.
On account of the short rounded-off head and the almost equally blunt tail
these creatures are called by the natives "cobras de dous cabezas," _i.e._
snakes with two heads, or they are known as "maes das formigas," _i.e._
mothers of ants, because of their predilection for taking up their quarters
in the nests of ants or termites. The scientific name refers of course to
their capability of moving forwards and backwards (ἀμφίς, at both ends, and
βαίνω, walk).
_A. fuliginosa_, one of the commonest species in South America and in the
West Indies, is chequered black and white. The skin of the body has about
two hundred rings, the tail about thirty. Total length between one and two
feet. A more or less distinct fold extends along each side of the body from
the neck to the tail, at the level where the dorsal scales originally
joined the ventral scales.
_Blanus_ is the only genus of the Mediterranean province. _B. cinereus_, of
Portugal, Spain south of the Cantabrian range, Morocco, and Algeria,
reaches a length of 10 inches, but such large specimens are rather rare.
The general colour of the living animal is pink with a brownish tinge and
with minute grey specks. The lateral lines or folds are well marked, and a
stronger transverse fold is placed behind the head. The body shows from one
hundred and ten to one hundred and twenty-five rings, the tail from twenty
to twenty-two; each body-ring contains about thirty little squares or
remnants of scales. There are a few pre-anal pores.
{567}I have sometimes found this species in Portugal whilst digging for
earth-worms in manure-heaps and similar moist places, where they lead the
same life as the worms except that they live upon them and upon insects.
When kept dry they become very thin and shrunken, but when put back into
moist soil they again become turgid and supple within a short time. Those
which I have kept in glass jars filled with rich mould throve very well,
living upon the tiny insects and worms which infest such compost soil; they
dug long tortuous channels, in which they moved forwards and sometimes
backwards, but they never came to the surface.
FAM. 18. PYGOPODIDAE.–Pleurodont, snake-shaped lizards, without fore-limbs,
but with the hind-limbs appearing as a pair of scaly flaps.
The shoulder-girdle is much reduced. The hind-limbs, although very small
and hidden within the scaly, almost fin-like flaps, still possess five
toes. The ischium appears externally as a small spur on either side of the
anal cleft. The eyes are devoid of movable lids, remaining open and
unprotected; the pupil is vertical. The ear is either concealed or exposed.
The tongue is fleshy, slightly forked and extensible. The body is covered
with roundish imbricating scales. The tail is very long and brittle. The
few genera of this undoubtedly natural family of unknown relationship
contain in all about ten species, restricted entirely to Australia,
Tasmania, and perhaps New Guinea. Next to nothing is known about their
habits, except that some of them eat other lizards.
_Pygopus lepidopus_ is distributed over the whole of Australia. It reaches
a total length of about 2 feet, 16 inches of which belong to the tail.
General colour coppery grey above, sometimes with several longitudinal
series of dark spots.
_Lialis burtoni_ of nearly the same size and equally wide distribution has
the hind-limbs reduced to extremely small, scarcely visible, narrow
appendages.
SUB-ORDER 3. CHAMAELEONTES.–_Acrodont Old-World Saurians with a laterally
compressed body, prehensile tail, and well-developed limbs with the digits
arranged in opposing, grasping, bundles of two and three respectively._
The Chameleons are an essentially African family. About half of the fifty
species known inhabit Madagascar, the others {568}the African continent.
One, the common Chameleon, is North African, extending into Andalucia; two
others occur in South Arabia and Socotra, and only one in Southern India
and Ceylon.
This sub-order is well distinguished from all other Saurians by several,
mostly unique, characters. The tongue is club-shaped and extremely
projectile, to a length equal to that of the body. The head is usually
described as forming a casque, with prominent crests and tubercles. There
is no tympanum and no tympanic cavity. The parietal bones, united into one,
extend backwards far beyond the occiput, and the tip of this projection is
met by a much-elongated supratemporal bone, which, partly fused with the
squamosal, helps to enclose a huge supratemporal fossa. The latter is
widely open behind. The postfronto-squamosal arch and the postorbital arch
are strong. The jugal is widely separated from the quadrate; the latter
stands vertically and is not reached by the pterygoid. There is no
columella cranii. The pre- and post-frontals often join to form a
supra-orbital roof. The nasals are very small and are excluded from the
nares, which are bordered entirely by the enlarged prefrontals and by the
maxillaries. The premaxillaries are small and carry no teeth. The latter
are acrodont, compressed and tricuspid, and are restricted to the
maxillaries and mandibles.
[Illustration: FIG. 148.–Map showing the distribution of Chameleons.]
The limbs are peculiar. Not only are they relatively long and very slender,
but two digits are permanently opposed to the other three. On the hand the
first three fingers form an inner bundle opposed to the outer, or fourth
and fifth fingers. On the foot the inner bundle is formed by the first and
second, the outer by the other toes. The shoulder-girdle is of the ordinary
Saurian type, but there are no clavicles and no interclavicle. The costal
sternum is well developed; the ribs posterior to those which meet the
sternum are very thin and elongated: they meet and fuse with their fellows
in the medio-ventral line. These hoops are not connected with their
neighbours in front or behind. The tail is prehensile by being rolled
downwards; it is not brittle and is incapable of being renewed. The skin is
not covered with scales, but with {569}granules. The eyes are very
remarkable. The eyeballs themselves are large, but the eyelids are united
into one fold with a small central opening. However, when the Chameleon is
asleep the margins of this opening sometimes become more slit-like. The
right and left eye can be, and are incessantly, moved separately from each
other, and the creature squints terribly. Each eyeball, together with the
pin-hole eyelid, is rolled up and down, backwards and forwards,
independently of the other eye. This is a unique feature, but it also
occurs in people who squint badly. The question "What, and how, do these
creatures see?" is therefore quite idle, especially since in reptiles
binocular vision does not exist at all and, consequently, cannot be
disturbed by squinting.
The tongue has attained an extraordinary development. The tongue proper
(Fig. 152) is club-shaped, and is covered with a sticky secretion. The base
or root of the tongue is very narrow, composed of extremely elastic fibres,
and is supported by a much-elongated copular piece of the hyoid. The
elastic part of the tongue is, so to speak, telescoped over the
style-shaped copula, and the whole apparatus is kept in a contracted state
like a spring in a tube.
[Illustration: FIG. 149.–A, Dorsal, B, ventral, and C, lateral view of the
skull of _Chamaeleon vulgaris_. × 1. _Cond_, occipital condyle; _EP_,
ectopterygoid; _Jug_, jugal; _Lac_, lacrymal; _Pal_, palatine; _Par_,
parietal; _Prf_, prefrontal; _Pt.f_, postfrontal; _Ptg_, pterygoid; _Q_,
quadrate; _Sq_, squamosal; _Vo_, vomer.]