typical form of _S. alba_ as well as in those of _S. lacustris_ subsp.
_reticulata_, and _S. carteri_; but the compact structure of the sponge
renders it a less suitable residence for other _incolæ_ than _S.
carteri_.
In the variety _bengalensis_, as it grows in the ponds at Port Canning,
a large number of arthropods, molluscs and other small animals take
shelter. Apart from protozoa and rotifers, which have as yet been little
studied, the following are some of the more abundant inhabitants of the
sponge:--The sea-anemone, _Sagartia schilleriana_ subsp. _exul_ (see p.
140), which frequently occurs in very large numbers in the broader
canals; the free-living nematode, _Oncholaimus indicus_[W], which makes
its way in and out of the oscula; molluscs belonging to several species
of the genus _Corbula_, which conceal themselves in the canals but are
sometimes engulfed in the growing sponge and so perish; young
individuals of the crab _Varuna litterata_, which hide among the
branches and ramifications of the larger sponges together with several
small species of prawns and the schizopod _Macropsis orientalis_[X]; the
peculiar amphipod _Quadrivisio bengalensis_[Y], only known from the
ponds at Port Canning, which breeds in little communities inside the
sponge; a small isopod[Z], allied to _Sphæroma walkeri_, Stebbing; the
larva of a may-fly, and those of at least two midges (Chironomidæ).
[Footnote W: O. von Linstow, Rec. Ind. Mus. i, p. 45
(1907).]
[Footnote X: W. M. Tattersall, _ibid._, ii, p. 236 (1908).]
[Footnote Y: T. R. R. Stebbing, _ibid._, i, p. 160 (1907);
and N. Annandale, _ibid._, ii, p. 107 (1908).]
[Footnote Z: Mr. Stebbing has been kind enough to examine
specimens of this isopod, which he will shortly describe in
the Records of the Indian Museum. _S. walkeri_, its nearest
ally, was originally described from the Gulf of Manaar,
where it was taken in a tow-net gathering (see Stebbing in
Herdman's Report on the Ceylon Pearl Fisheries, pt. iv, p.
31 (1905)).]
The peculiarly mixed nature (marine and lacustrine) of the fauna
associated with _S. alba_ in the ponds at Port Canning is well
illustrated by this list, and it only remains to be stated that little
fish (_Gobius alcockii_, _Barbus stigma_, _Haplochilus melanostigma_,
_H. panchax_, etc.) are very common and feed readily on injured sponges.
They are apparently unable to attack a sponge so long as its external
membrane is intact, but if this membrane is broken, they swarm round the
sponge and devour the parenchyma greedily. In fresh water one of these
fishes (_Gobius alcockii_, see p. 94) lays its eggs in sponges.
The chief enemy of the sponges at Port Canning is, however, not an
animal but a plant, viz., a green filamentous alga which grows inside
the sponge, penetrating its substance, blocking up its canals and so
causing it to die. Similar algæ have been described as being beneficial
to the sponges in which they grow[AA], but my experience is that they
are deadly enemies, for the growth of such algæ is one of the
difficulties which must be fought in keeping sponges alive in an
aquarium. The alga that grows in _S. alba_ often gives it a dark green
colour, which is, however, quite different from the bright green caused
by the presence of green corpuscles. The colour of healthy specimens of
the variety _bengalensis_ is a rather dark grey, which appears to be due
to minute inorganic particles taken into the cells of the parenchyma
from the exceedingly muddy water in which this sponge usually grows. If
the sponge is found in clean water, to whichever variety of the species
it belongs, it is nearly white with a slight yellowish tinge. Even when
the typical form is growing in close proximity to _S. proliferens_, as
is often the case, no trace of green corpuscles is found in its cells.
[Footnote AA: See M. and A. Weber in M. Weber's Zool. Ergeb.
Niederl. Ost-Ind. vol. i, p. 48, pl. v (1890).]
4. Spongilla cinerea*, _Carter_.
_Spongilla cinerea_, Carter, J. Bombay Soc. iii, p. 30, pl.
i, fig. 5, & Ann. Nat. Hist. (2) iv, p. 82, pl. iii, fig. 5
(1849).
_Spongilla cinerea_, Bowerbank, P. Zool. Soc. London, 1863,
p. 468, pl. xxxviii, fig. 19.
_Spongilla cinerea_, Carter, Ann. Nat. Hist. (5) vii, p. 263
(1881).
_Sponge_ forming large, flat sheets, never more than a few millimetres
in thickness, without a trace of branches, compact but very friable, of
a dark greyish colour; oscula small and inconspicuous or moderately
large, never prominent; membrane adhering closely to the sponge.
_Skeleton_ with well-defined but slender radiating fibres, which contain
very little spongin; transverse fibres close together but consisting for
the most part of one or two spicules only.
_Spicules._ Skeleton-spicules short, slender, sharply pointed, minutely
serrated or irregular in outline, almost straight. Gemmule-spicules very
small, rather stout, cylindrical, pointed, covered with relatively long
and stout spines which are either straight or directed towards the ends
of the spicule. Flesh-spicules fairly numerous in the external membrane
but by no means abundant in the parenchyma, very slender, gradually
pointed, covered uniformly with minute but distinct spines.
_Gemmules_ very small, only visible to the naked eye as minute specks,
as a rule numerous, free in the substance of the sponge, each provided
with a slender foraminal tubule and covered with a thick granular coat
in which the gemmule-spicules are arranged almost horizontally; a
horizontal layer of spicules also present on the external surface of the
gemmule; gemmule-spicules very numerous.
[Illustration: Fig. 10.--Gemmules and fragment of the skeleton of
_Spongilla cinerea_ (from type specimen), × 35.]
This sponge is easily distinguished from its Indian allies by the form
of its skeleton-spicules, which are, as Bowerbank expresses it,
"subspined"; that it to say, under a high power of the microscope their
outline appears to be very minutely serrated, although under a low power
they seem to be quite smooth. The spicules also are smaller than those
of _S. alba_, the only species with which _S. cinerea_ is likely to be
confused, and the gemmule has a well-developed foraminal tubule; the
skeleton is much closer than in _S. proliferens_.
TYPE in the British Museum; a piece in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--_S. cinerea_ is only known from the Bombay
Presidency. Carter obtained the original specimens at Bombay and the
only ones I have found were collected at Nasik, which is situated on the
eastern slopes of the Western Ghats, about 90 miles to the north-east.
BIOLOGY.--Carter's specimens were growing on gravel, rocks and stones at
the edge of "tanks," and were seldom covered for more than six months in
the year. Mine were on the sides of a stone conduit built to facilitate
bathing by conveying a part of the water of the Godaveri River under a
bridge. They were accompanied by _Spongilla indica_ and _Corvospongilla
lapidosa_ (the only other sponges I have found in running water in
India) and in the month of November appeared to be in active growth.
5. Spongilla travancorica*, _Annandale_.
_Spongilla travancorica_, Annandale, Rec. Ind. Mus. iii, p.
101, pl. xii, fig. 1 (1909).
_Sponge_ small, encrusting, without branches, hard but brittle; its
structure somewhat loose; colour dirty white. Dermal membrane in close
contact with the skeleton; pores and oscula inconspicuous. Surface
minutely hispid, smooth and rounded as a whole.
_Skeleton_ consisting of moderately stout and coherent radiating fibres
and well-defined transverse ones; a number of horizontal megascleres
present at the base and surface, but not arranged in any definite order.
No basal membrane.
[Illustration: Fig. 11.--Microscleres of _Spongilla travancorica_.
A=Gemmule-spicules; B=flesh-spicules (from type specimen), × 240.]
_Spicules._ Skeleton-spicules smooth, pointed at either end, moderately
stout, straight or curved, sometimes angularly bent; curvature usually
slight. Free microscleres abundant in the dermal membrane, slender,
nearly straight, gradually and sharply pointed, profusely ornamented
with short straight spines, which are much more numerous and longer at
the middle than near the ends. Gemmule-spicules stouter and rather
longer, cylindrical, terminating at each end in a sharp spine,
ornamented with shorter spines, which are more numerous and longer at
the ends than at the middle; at the ends they are sometimes directed
backwards, without, however, being curved.
_Gemmules_ firmly adherent to the support of the sponge, at the base of
which they form a layer one gemmule thick; each provided with at least
one foraminal tubule, which is straight and conical: two tubules, one at
the top and one at one side, usually present. Granular layer well
developed. Spicules arranged irregularly in this layer, as a rule being
more nearly vertical than horizontal but pointing in all directions, not
confined externally by a membrane; no external layer of horizontal
spicules.
_Measurements of Spicules and Gemmules._
Length of skeleton-spicules 0.289-0.374 mm.
Greatest diameter of skeleton-spicules 0.012-0.016 "
Length of free microscleres 0.08-0.096 "
Greatest diameter of free microscleres 0.002 mm.
Length of gemmule-spicules 0.1-0.116 "
Diameter of gemmule-spicule 0.008 mm.
" " gemmule 0.272-0.374 "
This species is easily distinguished from its allies of the subgenus
_Euspongilla_ by its adherent gemmules with their (usually) multiple
apertures and rough external surface.
TYPE in the collection of the Indian Museum.
HABITAT. Backwater near Shasthancottah, Travancore, in slightly brackish
water; on the roots of shrubs growing at the edge; November, 1908
(_Annandale_).
The specimens were dead when found.
6. Spongilla hemephydatia*, _Annandale_.
_Spongilla hemephydatia_, Annandale, Rec. Ind. Mus. iii, p.
275 (1909).
[Illustration: Fig. 12.--Gemmule and spicules of _Spongilla
hemephydatia_ (from type specimen).]
_Sponge_ soft, fragile, amorphous, of a dirty yellow colour, with large
oscula, which are not conspicuously raised above the surface but open
into very wide horizontal channels in the substance of the sponge. The
oscular collars are fairly well developed, but the subepidermal space is
not extensive.
_Skeleton_ diffuse, consisting of very fine radiating fibres, which are
crossed at wide and irregular intervals by still finer transverse ones;
very little chitinoid substance present.
_Spicules._ Skeleton-spicules smooth, slender, sharply pointed at both
ends, nearly straight. No true flesh-spicules. Gemmule-spicules straight
or nearly so, cylindrical, or constricted in the middle, obscurely
pointed or blunt, clothed with short, sharp, straight spines, which are
very numerous but not markedly longer at the two ends; these spicules
frequently found free in the parenchyma.
_Gemmules_ numerous, small, free, spherical, yellow, with a
well-developed granular coat (in which the spicules are arranged almost
horizontally) and external to it a fine membrane which in preserved
specimens becomes puckered owing to unequal contraction; each gemmule
with a single aperture provided with a straight, rather wide, but very
delicate foraminal tubule.
_Measurements of Spicules and Gemmules._
Length of skeleton-spicule 0.313 mm.
Breadth of skeleton-spicule 0.012 "
Length of gemmule-spicule 0.062 "
Breadth of gemmule-spicule 0.004 "
Diameter of gemmule 0.313-0.365 mm.
This sponge in its general structure bears a very close resemblance to
_Spongilla crateriformis_.
TYPE in the collection of the Indian Museum.
HABITAT. Growing on weeds at the edge of the Sur Lake, Orissa, October
1908. Only one specimen was taken, together with many examples of _S.
lacustris_ subsp. _reticulata_, _S. carteri_ and _S. crassissima_.
7. Spongilla crateriformis* (_Potts_).
_Meyenia crateriforma_, Potts, P. Ac. Philad. 1882, p. 12.
_Meyenia crateriformis, id., ibid._ 1887, p. 228, pl. v,
fig. 6, pl. x, fig. 5.
? _Ephydatia crateriformis_, Hanitsch, Nature, ii, p. 511
(1895).
_Ephydatia crateriformis_, Weltner, Arch. Naturg. lxi (i),
pp. 122, 134 (1895).
? _Ephydatia crateriformis_, Hanitsch, Irish Natural. iv, p.
125, pl. iv, fig. 5 (1895).
_Ephydatia indica_, Annandale, J. Asiat. Soc. Bengal, 1907,
p. 20 (figures poor).
_Ephydatia indica, id._, Rec. Ind. Mus. i, pp. 272, 279,
388, 391 (1907).
_Ephydatia crateriformis_, Scharff, European Animals, p. 34
(1907).
_Ephydatia crateriformis_, Annandale, P. U.S. Mus. xxxvii,
p. 402, fig. 1 (1909).
_Sponge_ very fragile, forming soft irregular masses on the roots and
stems of water-plants, between which it is sometimes stretched as a
delicate film, or thin layers or cushions on flat surfaces. Oscula
large, flat, circular, or of irregular shape, opening into broad
horizontal canals, which at their distal end are superficial and often
covered by the external membrane only. Colour white, yellowish, greyish,
or blackish.
_Skeleton_ very delicate; radiating fibres rarely consisting of more
than two parallel spicules; transverse fibres far apart, frequently
consisting of single spicules; very little spongin present.
[Illustration: Fig 13.--Spicules of _Spongilla crateriformis_.
A. From specimen taken in July in a tank on the Calcutta maidan. B. From
type specimen of _Ephydatia indica_ taken in the Indian Museum tank in
winter. Both figures × 240.]
_Spicules._ Skeleton-spicules feebly curved, slender, as a rule
irregular in outline, sometimes almost smooth; the ends as a rule
sharply pointed, often constricted off and expanded so as to resemble
spear-heads, occasionally blunt. No true flesh-spicules.
Gemmule-spicules often free in the parenchyma, cylindrical, slender,
very variable in length in different sponges, straight or nearly so, as
a rule with an irregular circle of strong straight or recurved spines at
either end resembling a rudimentary rotule, and with shorter straight
spines scattered on the shaft, sometimes without the rudimentary rotule,
either truncate at the ends or terminating in a sharp spine.
_Gemmules_ small, free, each surrounded by a thick granular layer in
which the spicules stand upright or nearly so, and covered externally by
a delicate but very distinct chitinous membrane; no horizontal spicules;
foramen situated at the base of a crater-like depression in the granular
coat, which is sometimes raised round it so as to form a conspicuous
rampart; a short, straight foraminal tubule.
The shape of the spicules is extremely variable, and sponges in which
they are very different occur in the same localities and even in the
same ponds. It is possible that the differences are directly due to
slight changes in the environment, for in one pond in Calcutta a form
with _Spongilla_-like gemmule-spicules appears to replace the typical
form, which is common in winter, during the hot weather and "rains." I
have not, however, found this to be the case in other ponds. Perhaps _S.
hemephydatia_ will ultimately prove to be a variety of this very
variable species, but its smooth and regular skeleton-spicules and
short-spined gemmule-spicules afford a ready method of distinguishing it
from _S. crateriformis_. The two sponges are easily distinguished from
all others in the subgenus _Euspongilla_ by the upright and regular
arrangement of their gemmule-spicules, for although in _S. proliferens_
and _S. travancorica_ some of the gemmule-spicules are nearly vertical,
their arrangement is always irregular, a large proportion of the
spicules make an acute angle with the inner coat of the gemmule and a
few as a rule lie parallel to it. The systematic position of _S.
crateriformis_ is almost exactly intermediate between _Euspongilla_ and
_Ephydatia_, to which genus it has hitherto been assigned. I think,
however, that taking into consideration its close relationship to _S.
hemephydatia_, it is best to assign it to _Spongilla_, as its
rudimentary rotules never form distinct disks. I have examined some of
Potts's original specimens from different American localities and can
detect no constant difference between them and Indian specimens.
TYPES in the United States National Museum; co-types in Calcutta.
GEOGRAPHICAL DISTRIBUTION.--This sponge was originally described from
North America (in which continent it is widely distributed) and has been
recorded from the west of Ireland with some doubt. In India and Burma it
is widely distributed. BENGAL, Calcutta and neighbourhood (_Annandale_);
Sonarpur, Gangetic delta (_Annandale_); BOMBAY PRESIDENCY, Igatpuri
Lake, W. Ghats (altitude _ca._ 2,000 feet) (_Annandale_); MADRAS
PRESIDENCY, neighbourhood of Madras town (_J. R. Henderson_); Museum
compound, Egmore (Madras town) (_Annandale_); near Bangalore (alt. _ca._
3,000 ft.), Mysore State (Annandale); Ernakulam, Cochin (_G. Mathai_):
BURMA, Kawkareik, interior of Amherst district, Tenasserim, and the
Moulmein waterworks in the same district (_Annandale_).[AB]
[Footnote AB: Mr. C. A. Paiva, Assistant in the Indian
Museum, has lately (March 31st, 1911) obtained specimens of
_S. crateriformis_ in a small pond of fresh water on Ross
Island in the Andaman group. The existence of this widely
distributed species on an oceanic island is noteworthy.]
BIOLOGY.--_S. crateriformis_ flourishes in Calcutta throughout the year.
Here it is usually found adhering to the roots of water-plants,
especially _Pistia_ and _Limnanthemum_. In the case of the former it
occurs at the surface, in that of the latter at the bottom. When growing
near the surface or even if attached to a stone at the bottom in clear
water, it is invariably of a pale yellowish or greyish colour. When
growing on the roots of _Limnanthemum_ in the mud of the Gangetic
alluvium, however, it is almost black, and when growing in the reddish
muddy waters of the tanks round Bangalore of a reddish-brown colour.
This appears to be due entirely to the absorption of minute particles of
inorganic matter by the cells of the parenchyma. If black sponges of the
species are kept alive in clean water, they turn pure white in less than
a week, apparently because these particles are eliminated. When growing
on stones the sponge, as found in India, often conforms exactly with
Potts's description: "a filmy grey sponge, branching off here and there
... yet with a curious lack of continuity...."
The wide efferent canals of this sponge afford a convenient shelter to
small crustacea, and the isopod _Tachæa spongillicola_, Stebbing (see p.
94), is found in them more abundantly than in those of any other sponge.
This is especially the case when the sponge is growing at the bottom. On
the surface of the sponge I have found a peculiar protozoon which
resembles the European _Trichodina spongillæ_ in general structure but
belongs, I think, to a distinct species, if not to a distinct genus.
Subgenus B. EUNAPIUS, _J. E. Gray_.
_Eunapius_, J. E. Gray (_partim_), P. Zool. Soc. London,
1867, p. 552.
_Spongilla_ (_s. str._), Vejdovsky, in Potts's "Fresh-Water
Sponges," P. Ac. Philad. 1887, p. 172.
_Spongilla_ (_s. str._), Weltner, in Zacharias's Tier- und
Pflanzenwelt des Süsswassers, i, p. 214 (1891).
_Spongilla_ (_s. str._), Annandale, Zool. Jahrb., Syst.
xxvii, p. 559 (1909).
TYPE, _Spongilla carteri_, Carter.
Spongillæ in which the gemmules are covered with layers of distinct
polygonal air-spaces with chitinous walls.
The gemmules are usually fastened together in groups, which may either
be free in the sponge or adhere to its support as a "pavement layer";
sometimes, however, they are not arranged in this manner, but are quite
independent of one another. The skeleton is usually delicate, sometimes
very stout (_e. g._, in _S. nitens_, Carter).
The term _Eunapius_ here used is not quite in the original sense, for
Gray included under it Bowerbank's _Spongilla paupercula_ which is now
regarded as a form of _S. lacustris_. His description, nevertheless,
fits the group of species here associated except in one particular,
viz., the smoothness of the gemmule-spicules to which he refers, for
this character, though a feature of _S. carteri_, is not found in
certain closely allied forms. The use of "_Spongilla_" in a double sense
may be avoided by the adoption of Gray's name.
The subgenus _Eunapius_ is, like _Euspongilla_, cosmopolitan. It is not,
however, nearly so prolific in species. Four can be recognized in India,
two of which range, in slightly different forms, as far north as Europe,
one of them also being found in North America, Northern Asia, and
Australia.
8. Spongilla carteri* _Carter_ (_Bowerbank_, in litt.). (Plate II. fig.
1.)
_Spongilla friabilis_?, Carter (_nec_ Lamarck), J. Bombay
Asiat. Soc. iii, p. 31, pl. i, fig. 3 (1849), & Ann. Nat.
Hist. (2) iv, p. 83, pl. ii. fig. 3 (1849).
_Spongilla carteri_, Carter, Ann. Nat. Hist. (3) iii, p.
334, pl. viii, figs. 1-7 (1859).
_Spongilla carteri_, Bowerbank, P. Zool. Soc. London, 1863,
p. 469, pl. xxxviii, fig. 20.
_Eunapius carteri_, J. E. Gray, _ibid._ 1867, p. 552.
_Spongilla carteri_, Carter, Ann. Nat. Hist. (5) vii, p. 86
(1881).
_Spongilla carteri_, _id._, _ibid._ x, p. 369 (1882).
_Spongilla carteri_, Potts, P. Ac. Philad. 1887, p. 194.
_Spongilla carteri_, Weltner, Arch. Naturg. lxi (i), pp.
117, 134 (1895).
_Spongilla carteri_, Kirkpatrick, P. Zool. Soc. London, 1906
(i), p. 219, pl. xv, figs. 3, 4 (? figs. 1, 2).
_Spongilla carteri_, Annandale, J. Asiat. Soc. Bengal, 1906,
p. 188, pl. i, fig. 1.
_Spongilla carteri_, Willey, Spolia Zeyl. iv, p. 184 (1907).
_Spongilla carteri_, Annandale, _ibid._ vii, p. 63, pl. 1,
fig. 1 (1910).
[Illustration: Fig. 14.--Gemmule of _Spongilla carteri_ (from Calcutta),
as seen in optical section, × 140.]
_Sponge_ massive, as a rule with the surface smooth and rounded,
occasionally bearing irregular ridges, which may even take the form of
cockscombs; the oscula large, rounded, conspicuous but not raised above
the surface of the sponge, leading into broad vertical canals; the
lateral canals, except in the immediate vicinity of the central vertical
ones, not very broad; the oscular collars extending for a considerable
distance over the oscula in living or well-preserved specimens, never
standing out from the surface; the oscula never surrounded by radiating
furrows. The inhalent pores surrounded externally by unmodified cells of
the external membrane. Colour greyish, sometimes with a flush of green
on the external surface.
The sponge has a peculiarly strong and offensive smell.
_Skeleton_ fairly compact, with well-developed radiating fibres; the
transverse fibres splayed out at either end so that they sometimes
resemble a pair of fans joined together by the handles (fig. 3, p. 33).
A moderate amount of spongin present.
_Spicules._ Skeleton-spicules smooth, pointed, nearly straight, never
very stout but somewhat variable in exact proportions. Gemmule-spicules
similar but much smaller. (There are no true flesh-spicules, but
immature skeleton-spicules may easily be mistaken for them.)
_Gemmules_ as a rule numerous, spherical or flattened at the base,
variable in size, each covered by a thick coat consisting of several
layers of relatively large polygonal air-spaces. A single aperture
surrounded by a crater-like depression in the cellular coat and provided
with a foraminal tubule resembling an inverted bottle in shape. (This
tubule, which does not extend beyond the surface of the cellular coat,
is liable to be broken off in dried specimens.) The spicules variable in
quantity, arranged irregularly among the spaces of the cellular coat and
usually forming a sparse horizontal layer on its external surface. Each
gemmule contained in a cage of skeleton-spicules, by the pressure of
which it is frequently distorted.
8_a._ Var. mollis*, nov.
This variety is characterized by a paucity of skeleton-spicules. The
sponge is therefore soft and so fragile that it usually breaks in pieces
if lifted from the water by means of its support. Owing to the paucity
of skeleton-spicules, which resemble those of the typical form
individually, the radiating and transverse fibres are extremely
delicate.
Common in Calcutta.
8_b._ Var. cava*, nov.
This variety is characterized by the fact that the oscula open into
broad horizontal canals, the roof of which is formed by a thin layer of
parenchyma and skeleton or, in places, of the external membrane only.
The skeleton is loose and fragile, and the living sponge has a peculiar
glassy appearance. In spirit the colour is yellowish, during life it is
greenish or white.
Taken at Bombay; November, 1907.
8_c._ Var. lobosa*, nov.
The greater part of the sponge in this variety consists of a number of
compressed but pointed vertical lobes, which arise from a relatively
shallow, rounded base, in which the oscula occur. The dried sponge has a
yellowish colour.
Apparently common in Travancore.
* * * * *
I cannot distinguish these three "varieties"[AC] from the typical form
as distinct species; indeed, their status as varieties is a little
doubtful in two cases out of the three. Var. _cava_ appears to be a
variety in the strict sense of the word (see p. 18), for it was found on
the island of Bombay, the original locality of the species, growing side
by side with the typical form. Var. _lobosa_, however, should perhaps be
regarded as a subspecies rather than a variety, for I have received
specimens from two localities in the extreme south-west of India and
have no evidence that the typical form occurs in that part of the
country. Evidence, however, is rather scanty as regards the occurrence
of freshwater sponges in S. India. Var. _mollis_, again, may be a phase
directly due to environment. It is the common form in the ponds of
certain parts (_e. g._ in the neighbourhood of the Maidan and at
Alipore) of the Calcutta municipal area, but in ponds in other parts
(_e. g._ about Belgatchia) of the same area, only the typical form is
found. It is possible that the water in the former ponds may be
deficient in silica or may possess some other peculiarity that renders
the production of spicules difficult for _S. carteri_; but this seems
hardly probable, for _S. crassissima_, a species with a rather dense
siliceous skeleton, flourishes in the same ponds. I have noticed that in
ponds in which the aquatic vegetation is luxuriant and such genera of
plants as _Pistia_ and _Limnanthemum_ flourish, there is always a
tendency for _S. carteri_ to be softer than in ponds in which the
vegetation is mostly cryptogamic, and in Calcutta those parts of the
town in which sponges of this species produce most spicules are those in
which a slight infiltration of brackish water into the ponds may be
suspected; but in the interior of India, in places where the water is
absolutely fresh, hard specimens seem to be the rule rather than the
exception.
[Footnote AC: The only complete European specimen of the
species I have seen differs considerably in outward form
from any Indian variety, consisting of a flat basal area
from which short, cylindrical turret-like branches arise.
This specimen is from Lake Balaton in Hungary and was sent
me by Prof. von Daday de Dees of Buda-Pesth.]
_S. carteri_ is closely related to _S. nitens_, Carter (Africa, and
possibly S. America), but differs from that species in its comparatively
slender, sharp skeleton-spicules and smooth gemmule-spicules. It may
readily be distinguished from all other Indian freshwater sponges by its
large, deep, round oscula, but this feature is not so marked in var.
_lobosa_ as in the other forms. The typical form and var. _mollis_ grow
to a larger size than is recorded for any other species of the family. I
possess a specimen of the typical form from the neighbourhood of
Calcutta which measures 30 × 27 cm. in diameter and 19.5 cm. in depth,
and weighs (dry) 24-3/4 oz. The base of this specimen, which is solid
throughout, is nearly circular, and the general form is mound-shaped.
Another large specimen from Calcutta is in the form of an irregular
wreath, the greatest diameter of which is 34 cm. This specimen weighs
(dry) 16-1/4 oz. Both these specimens probably represent the growth of
several years.
TYPES.--The types of the varieties _mollis_, _cava_ and _lobosa_ are in
the collection of the Indian Museum. I regard as the type of the species
the specimen sent by Carter to Bowerbank and by him named _S. carteri_,
although, owing to some confusion, Carter's description under this name
appeared some years before Bowerbank's. This specimen is in the British
Museum, with a fragment in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--The range of the species extends westwards
to Hungary, southwards to Mauritius and eastwards to the island of
Madura in the Malay Archipelago; a specimen from Lake Victoria Nyanza in
Central Africa has been referred to it by Kirkpatrick (P. Zool. Soc.
London, 1906 (i), p. 219), but I doubt whether the identification is
correct. In India _S. carteri_ is by far the most universally
distributed and usually much the commonest freshwater sponge; it is one
of the only two species as yet found in Ceylon. Specimens are known from
the following localities:--PUNJAB, Lahore (_J. Stephenson_): BOMBAY
PRESIDENCY, island of Bombay (_Carter_, _Kirkpatrick_, _Annandale_);
Igatpuri, W. Ghats (alt. _ca._ 2,000 ft.) (_Annandale_): UNITED
PROVINCES (plains), Agra (_Kirkpatrick_); Lucknow: HIMALAYAS, Bhim Tal,
Kumaon (alt. 4,500 ft.) (_Annandale_); Tribeni, Nepal (_Hodgart_):
BENGAL, Calcutta and neighbourhood; Rajshahi (Rampur Bhulia) on the R.
Ganges about 150 miles N. of Calcutta (_Annandale_); Berhampur,
Murshidabad district (_R. E. Lloyd_); Pusa, Darbbhanga district
(_Bainbrigge Fletcher_); Siripur, Saran district, Tirhut (_M.
Mackenzie_); Puri and the Sur Lake, Orissa (_Annandale_): MADRAS
PRESIDENCY, near Madras town (_J. R. Henderson_); Madura district (_R.
Bruce Foote_); Bangalore (_Annandale_) and Worgaum, Mysore State
(2,500-3,000 ft.); Ernakulam and Trichur, Cochin (_G. Mathai_);
Trivandrum and the neighbourhood of C. Comorin, Travancore (var.
_lobosa_) (_R. S. N. Pillay_): BURMA, Kawkareik, interior of Amherst
district, Tenasserim (_Annandale_); Rangoon (_Annandale_); Bhamo, Upper
Burma (_J. Coggin Brown_): CEYLON, Peradeniya (_E. E. Green_); outlet of
the Maha Rambaikulam between Vavuniya and Mamadu, Northern Province
(_Willey_); Horowapotanana, between Trincomalee and Anuradihapura,
North-Central Province (_Willey_).
BIOLOGY.--_S. carteri_ usually grows in ponds and lakes; I have never
seen it in running water. Mr. Mackenzie found it on the walls of old
indigo wells in Tirhut.
The exact form of the sponge depends to some extent on the forces acting
on it during life. At Igatpuri, for instance, I found that specimens
attached to the stems of shrubs growing in the lake and constantly
swayed by the wind had their surface irregularly reticulated with high
undulating ridges, while those growing on stones at the bottom of a
neighbouring pond were smooth and rounded.
Sponges of this species do not shun the light.
In Calcutta _S. carteri_ flourishes during the cold weather (November to
March). By the end of March many specimens that have attached themselves
to delicate stems such as those of the leaves of _Limnanthemum_, or to
the roots of _Pistia stratiotes_, have grown too heavy for their support
and have sunk down into the mud at the bottom of the ponds, in which
they are quickly smothered. Others fixed to the end of branches
overhanging the water or to bricks at the edge have completely dried up.
A large proportion, however, still remain under water; but even these
begin to show signs of decay at this period. Their cells migrate to the
extremities of the sponge, leaving a mass of gemmules in the centre, and
finally perish.
Few sponges exist in an active condition throughout the hot weather. The
majority of those that do so exhibit a curious phenomenon. Their surface
becomes smoothly rounded and they have a slightly pinkish colour; the
majority of the cells of their parenchyma, if viewed under a high power
of the microscope, can be seen to be gorged with very minute drops of
liquid. This liquid is colourless in its natural condition, but if the
sponge is plunged into alcohol the liquid turns of a dark brown colour
which stains both the alcohol and the sponge almost instantaneously.
Probably the liquid represents some kind of reserve food-material. Even
in the hot weather a few living sponges of the species may be found that
have not this peculiarity, but, in some ponds at any rate, the majority
that survive assume the peculiar summer form, which I have also found at
Lucknow.
Reproduction takes place in _S. carteri_ in three distinct ways, two of
which may be regarded as normal, while the third is apparently the
result of accident. If a healthy sponge is torn into small pieces and
these pieces are kept in a bowl of water, little masses of cells
congregate at the tips of the radiating fibres of the skeleton and
assume a globular form. At first these cells are homogeneous, having
clear protoplasm full of minute globules of liquid. The masses differ
considerably in size but never exceed a few millimetres in diameter. In
about two days differentiation commences among the cells; then spicules
are secreted, a central cavity and an external membrane formed, and an
aperture, the first osculum, appears in the membrane. In about ten days
a complete young sponge is produced, but the details of development have
not been worked out.
The most common normal form of reproduction is by means of gemmules,
which are produced in great numbers towards the end of the cold weather.
If small sponges are kept alive in an aquarium even at the beginning of
the cold weather, they begin to produce gemmules almost immediately, but
these gemmules although otherwise perfect, possess few or no
gemmule-spicules. If the sponge becomes desiccated at the end of the
cold weather and is protected in a sheltered place, some or all of the
gemmules contained in the meshes of its skeleton germinate _in situ_ as
soon as the water reaches it again during the "rains." It is by a
continuous or rather periodical growth of this kind, reassumed season
after season, that large masses of sponge are formed. In such masses it
is often possible to distinguish the growth of the several years, but as
a rule the layers become more or less intimately fused together, for no
limiting membrane separates them. A large proportion of the gemmules
are, however, set free and either float on the surface of the water that
remains in the ponds or are dried up and carried about by the wind. In
these circumstances they do not germinate until the succeeding cold
weather, even if circumstances other than temperature are favourable;
but as soon as the cold weather commences they begin to produce new
sponges with great energy.
Sexual reproduction, the second normal form, takes place in _S. carteri_
mainly if not only at the approach of a change of season, that is to say
about March, just before the hot weather commences, and about November,
just as the average temperature begins to sink to a temperate level. At
these seasons healthy sponges may often be found full of eggs and
embryos, which lie in the natural cavities of the sponge without
protecting membrane.
In the ponds of Calcutta a large number of animals are found associated
in a more or less definite manner with _Spongilla carteri_. Only one,
however, can be described with any degree of certainty as being in
normal circumstances an enemy, namely the larva of _Sisyra indica_,[AD]
and even in the case of this little insect it is doubtful how far its
attacks are actually injurious to the sponge. The larva is often found
in considerable numbers clinging to the oscula and wide efferent canals
of _S. carteri_, its proboscis inserted into the substance of the
sponge. If the sponge dies and the water becomes foul the larvæ swim or
crawl away. If the sponge dries up, they leave its interior (in which,
however, they sometimes remain for some days after it has become dry)
and pupate in a silken cocoon on its surface. Hence they emerge as
perfect insects after about a week.
[Footnote AD: Needham. Rec. Ind. Mus. iii, p. 206 (1909).]
An animal that may be an enemy of _S. carteri_ is a flat-worm (an
undescribed species of _Planaria_) common in its larger canals and
remarkable for the small size of its pharynx. The same worm, however, is
also found at the base of the leaves of bulrushes and in other like
situations, and there is no evidence that it actually feeds on the
sponge. Injured sponges are eaten by the prawn _Palæmon lamarrei_,
which, however, only attacks them when the dermal membrane is broken. A
_Tanypus_ larva (Chironomid Diptera) that makes its way though the
substance of the sponge may also be an enemy; it is commoner in decaying
than in vigorous sponges.
The presence of another Chironomid larva (_Chironomus_, sp.) appears to
be actually beneficial. In many cases it is clear that this larva and
the sponge grow up together, and the larva is commoner in vigorous than
in decayed sponges. Unlike the _Tanypus_ larva, it builds parchment-like
tubes, in which it lives, on the surface of the sponge. The sponge,
however, often grows very rapidly and the larva is soon in danger of
being engulfed in its substance. The tube is therefore lengthened in a
vertical direction to prevent this catastrophe and to maintain
communication with the exterior. The process may continue until it is
over an inch in length, the older part becoming closed up owing to the
pressure of the growing sponge that surrounds it. Should the sponge die,
the larva lives on in its tubes without suffering, and the ends of tubes
containing larvæ may sometimes be found projecting from the worn surface
of dead sponges. The larva does not eat the sponge but captures small
insects by means of a pair of legs on the first segment of its thorax.
In so doing it thrusts the anterior part of its body out of the tube, to
the inner surface of which it adheres by means of the pair of false legs
at the tip of the abdomen. This insect, which is usually found in the
variety _mollis_, appears to do good to the sponge in two ways--by
capturing other insects that might injure it and by giving support to
its very feeble skeleton.
A precisely similar function, so far as the support of the sponge is
concerned, is fulfilled by the tubular zooecia of a phase of the
polyzoon _Plumatella fruticosa_ (see p. 218) which in India is more
commonly found embedded in the substance of _S. carteri_ than in that of
any other species, although in Great Britain it is generally found in
that of _S. lacustris_, which is there the commonest species of
freshwater sponge.
Another animal that appears to play an active part in the oeconomy of
the sponge is a peculiar little worm (_Chætogaster spongillæ_) also
found among the zooecia of _Plumatella_ and belonging to a widely
distributed genus of which several species are found in association with
pond-snails. _Chætogaster spongillæ_ often occurs in enormous numbers in
dead or dying sponges of _S. carteri_, apparently feeding on the
decaying organic matter of the sponge and assisting by its movements in
releasing numerous gemmules. In so doing it undoubtedly assists in the
dissemination of the species.
Major J. Stephenson (Rec. Ind. Mus. v, p. 233) has recently found two
other species of oligochætes inhabiting _S. carteri_ var. _lobosa_ from
Travancore. Both these species, unlike _Chætogaster spongillæ_, belong
to a genus that is vegetarian in habits. One of them, _Nais pectinata_,
has not yet been found elsewhere, while the other, _Nais communis_, has
a very wide distribution. The latter, however, occurs in the sponge in
two forms--one with eyes, the other totally blind. The blind form (_N.
communis_ var. _cæca_) has only been found in this situation, but the
other (var. _punjabensis_) lives free as well as in association with the
sponge, in which the blind form was the commoner of the two.
The majority of the animals found in association with _S. carteri_ gain
shelter without evident assistance to the sponge. This is the case as
regards the little fish (_Gobius alcockii_), one of the smallest of the
vertebrates (length about 1/2 inch), which lays its eggs in the patent
oscula, thus securing for them a situation peculiarly favourable to
their development owing to the constant current of water that passes
over them. In the absence of sponges, however, this fish attaches its
eggs to the floating roots of the water-plant _Pistia stratiotes_.
Numerous small crustacea[AE] also take temporary or permanent refuge in
the cavities of _S. carteri_, the most noteworthy among them being the
Isopod _Tachæa spongillicola_[AF], the adults of which are found in the
canal of this and other sponges, while the young cling to the external
surface of the carapace of _Palæmon lamarrei_ and other small prawns.
Many worms and insects of different kinds also enter the canals of _S.
carteri_, especially when the sponge is becoming desiccated; from
half-dry sponges numerous beetles and flies may be bred, notably the
moth-fly _Psychoda nigripennis_[AG] of which enormous numbers sometimes
hatch out from such sponges.
[Footnote AE: According to the late Rai Bahadur R. B.
Sanyal, freshwater sponges are called in Bengali "shrimps'
nests." From his description it is evident that he refers
mainly to _S. carteri_ (see Hours with Nature, p. 46;
Calcutta 1896).]
[Footnote AF: Stebbing, J. Linn. Soc. xxx, p. 40; Annandale,
Rec. Ind. Mus. i, p. 279.]
[Footnote AG: Brunetti, Rec. Ind. Mus. ii, p. 376 (1908).]
As the sponge grows it frequently attaches itself to small molluscs such
as the young of _Vivipara bengalensis_, which finally become buried in
its substance and thus perish. Possibly their decaying bodies may afford
it nourishment, but of the natural food of sponges we know little. _S.
carteri_ flourishes best and reaches its largest size in ponds used for
domestic purposes by natives of India, and thrives in water thick with
soap-suds. It is possible, though direct proof is lacking, that the
sponge does good in purifying water used for washing the clothes,
utensils, and persons of those who drink the same water, by absorbing
decaying animal and vegetable matter from it.
Various minute algæ are found associated with _S. carteri_, but of these
little is yet known. The green flush sometimes seen on the surface of
the typical form is due to the fact that the superficial cells of the
parenchyma contain green corpuscles. These, however, are never very
numerous and are not found in the inner parts of the sponge, perhaps
owing to its massive form. It is noteworthy that these green bodies
flourish in large numbers throughout the substance of sponges of _S.
proliferens_, a species always far from massive, growing in the same
ponds as _S. carteri_.
9. Spongilla fragilis, _Leidy_.
_Spongilla fragilis_, Leidy, P. Ac. Philad. 1851, p. 278.
_Spongilla lordii_, Bowerbank, P. Zool. Soc. London, 1863,
p. 466, pl. xxxviii, fig. 17.
_Spongilla contecta_, Noll, Zool. Garten*, 1870, p. 173.
_Spongilla ottavænsis_, Dawson, Canad. Nat.* (new series)
viii, p. 5 (1878).
_Spongilla sibirica_, Dybowski, Zool. Anz., Jahr. i, p. 53
(1878).
_Spongilla morgiana_, Potts, P. Ac. Philad. 1880, p. 330.
_Spongilla lordii_, Carter, Ann. Nat. Hist. (5) vii, p. 89,
pl. vi, fig. 13 (1881).
_Spongilla sibirica_, Dybowski, Mém. Ac. St. Pétersb. (7)
xxx, no. x, p. 10, fig. 12.
_Spongilla glomerata_, Noll, Zool. Anz., Jahr. ix, p. 682
(1886).
_Spongilla fragilis_, Vejdovsky, P. Ac. Philad. 1887, p.
176.
_Spongilla fragilis_, Potts, _ibid._ p. 197, pl. v, fig. 2;
pl. viii, figs. 1-4.
_Spongilla fragilis_, Weltner, Arch. Naturg. lix (1), p.
266, pl. ix, figs. 18-20 (1893).
_Spongilla fragilis_, _id._, Arch. Naturg. lxi (i), p. 117
(1895).
_Spongilla fragilis_, _id._, in Semon's Zool. Forsch. in
Austral. u. d. Malay. Arch. v, part v, p. 523.
_Spongilla fragilis_, Annandale, P. U.S. Mus. xxxvii, p. 402
(1909).
_Spongilla fragilis_, _id._, Annot. Zool. Japon. vii, part
ii, p. 106, pl. ii, fig. 1 (1909).
_Sponge_ flat, lichenoid, never of great thickness, devoid of branches,
dense in texture but very friable; colour brown, green, or whitish;
oscula numerous, small, flat, distinctly star-shaped.
_Skeleton_ with well defined radiating and transverse fibres, which are
never strong but form a fairly dense network with a small amount of
spongin.
_Spicules._ Skeleton-spicules smooth, sharply pointed, moderately stout,
as a rule nearly straight. No flesh-spicules. Gemmule-spicules
cylindrical, blunt or abruptly pointed, nearly straight, covered with
relatively stout, straight, irregular spines, which are equally
distributed all over the spicule.
_Gemmules_ bound together in free groups of varying numbers and forming
a flat layer at the base of the sponge; each gemmule small in size,
surrounded by a thick cellular coat of several layers; with a relatively
long and stout foraminal tubule, which projects outwards through the
cellular coat at the sides of the group or at the top of the basal layer
of gemmules, is usually curved, and is not thickened at the tip; more
than one foraminal tubule sometimes present on a single gemmule;
gemmule-spicules arranged horizontally or at the base of the cellular
coat.
The species as a species is easily distinguished from all others, its
nearest ally being the N. American _S. ingloriformis_ with sparsely
spined skeleton-spicules which are very few in number, and gemmule
groups in which the foraminal tubules all open downwards.
Several varieties of _S. fragilis_ have been described in Europe and
America.
TYPE.--Potts refers to the type as being in the Academy of Natural
Sciences at Philadelphia.
GEOGRAPHICAL DISTRIBUTION.--All over Europe and N. America; also in
Siberia, Australia, and S. America. The species is included in this work
in order that its Asiatic local races may be fitly described.
9 _a._ Subsp. calcuttana*, nov.
? _Spongilla decipiens_, Weltner (_partim_), Arch. Naturg.
lxi (i), pp. 117, 134 (1895).
_Spongilla decipiens_, Annandale, Journ. As. Soc. Beng.
1906, p. 57.
_Spongilla fragilis_, _id._, Rec. Ind. Mus. i, p. 390
(1907).
[Illustration: Fig. 15.--_Spongilla fragilis_ subsp. _calcuttana_.
A=group of gemmules, × 70; B=spicules, × 240. From type specimen.]
This local race, which is common in Calcutta, is distinguished from the
typical form mainly by the shape of its skeleton-spicules, most of which
are abruptly pointed or almost rounded at the tips, sometimes bearing a
minute conical projection at each end. The gemmule-spicules, which are
usually numerous, are slender. The foraminal tubules are usually long
and bent, but are sometimes very short and quite straight. The colour is
usually greyish, occasionally brown.
I have not found this race except in Calcutta, in the ponds of which it
grows on bricks or, very commonly, on the stems of bulrushes, often
covering a considerable area.
TYPE in the Indian Museum.
9 _b._ Subsp. decipiens*, _Weber_.
_Spongilla decipiens_, Weber, Zool. Ergeb. Niederländ.
Ost-Ind. i, p. 40, pl. iv, figs. 1-5 (1890).
This (?) local race is distinguished by the fact that the foraminal
tubules are invariably short and straight and thickened at the tips, and
that gemmule-spicules do not occur on the external surface of the
cellular coat of the gemmules.
I include Weber's _Spongilla decipiens_ in the Indian fauna on the
authority of Weltner, who identified specimens from the Museum "tank,"
Calcutta, as belonging to this form. All, however, that I have examined
from our "tank" belong to the subspecies _calcuttana_, most of the
skeleton-spicules of which are much less sharp than those of
_decipiens_. By the kindness of Prof. Max Weber I have been able to
examine a co-type of his species, which is probably a local race
peculiar to the Malay Archipelago.
TYPE in the Amsterdam Museum; a co-type in Calcutta.
Perhaps the Japanese form, which has spindle-shaped gemmule-spicules
with comparatively short and regular spines, should be regarded as a
third subspecies, and the Siberian form as a fourth.
10. Spongilla gemina*, sp. nov.
_Sponge_ forming small, shallow, slightly dome-shaped patches of a more
or less circular or oval outline, minutely hispid on the surface,
friable but moderately hard. Oscula numerous but minute and
inconspicuous, never star-shaped. Dermal membrane adhering closely to
the sponge. Colour grey or brown.
_Skeleton_ forming a close and regular network at the base of the
sponge, becoming rather more diffuse towards the external surface; the
radiating and the transverse fibres both well developed, of almost equal
diameter. Little spongin present.
_Spicules._ Skeleton-spicules slender, smooth, sharply pointed. No
flesh-spicules. Gemmule-spicules long, slender, cylindrical, blunt or
bluntly pointed, somewhat irregularly covered with minute straight
spines.
_Gemmules_ small, bound together in pairs, as a rule free in the
parenchyma but sometimes lightly attached at the base of the sponge.
Each gemmule flattened on the surface by which it is attached to its
twin, covered with a thin coat of polygonal air-spaces which contains
two layers of gemmule-spicules crossing one another irregularly in a
horizontal plane. One or two foraminal tubules present on the surface
opposite the flat one, bending towards the latter, often of considerable
length, cylindrical and moderately stout.
TYPE in the Indian Museum.
This species is closely allied to _S. fragilis_, from which it may be
distinguished by the curious twinned arrangement of its gemmules. It
also differs from _S. fragilis_ in having extremely small and
inconspicuous oscula.
_Locality._ I only know this sponge from the neighbourhood of Bangalore,
where Dr. Morris Travers and I found it in October, 1910 growing on
stones and on the leaves of branches that dipped into the water at the
edge of a large tank.
11. Spongilla crassissima*, _Annandale_.
_Spongilla crassissima_, Annandale, J. Asiat. Soc. Bengal,
1907, p. 17, figs. 2, 3.
_Spongilla crassissima_, _id._, _ibid._ p. 88.
_Spongilla crassissima_, _id._, Rec. Ind. Mus. i. p. 390,
pl. xiv, fig. 4 (1907).
_Sponge_ very hard and strong, nearly black in colour, sometimes with a
greenish tinge, forming spherical, spindle-shaped or irregular masses
without branches but often several inches in diameter. Oscula circular
or star-shaped, usually surrounded by radiating furrows; pores normally
contained in single cells. External membrane closely adherent to the
sponge except immediately round the oscula.
_Skeleton_ dense, compact and only to be broken by the exercise of
considerable force; radiating and transverse fibres not very stout but
firmly bound together by spongin (fig. 6, p. 38), which occasionally
extends between them as a delicate film; their network close and almost
regular.
_Spicules._ Skeleton-spicules smooth, feebly curved, sausage-shaped but
by no means short, as a rule bearing at each end a minute conical
projection which contains the extremity of the axial filament. No
flesh-spicules. Gemmule-spicules closely resembling those of _S.
fragilis_ subsp. _calcuttana_, but as a rule even more obtuse at the
ends.
_Gemmules_ as in _S. fragilis_ subsp. _calcuttana_; a basal layer of
gemmules rarely formed.
11 _a._ Var. crassior*, _Annandale_.
_Spongilla crassior_, Annandale, Rec. Ind. Mus. i, p. 389,
pl. xiv, fig. 3 (1907).
This variety differs from the typical form chiefly in its even stronger
skeleton (fig. 3, p. 33) and its stouter skeleton-spicules, which do not
so often possess a terminal projection. The sponge is of a brownish
colour and forms flat masses of little thickness but of considerable
area on sticks and on the stems of water-plants.
TYPES.--The types of both forms are in the Indian Museum. Co-types have
been sent to London.
GEOGRAPHICAL DISTRIBUTION.--This sponge is only known from Bengal. The
variety _crassior_ was found at Rajshahi (Rampur Bhulia) on the Ganges,
about 150 miles N. of Calcutta, while the typical form is fairly common
in the "tanks" of Calcutta and very abundant in the Sur Lake near Puri
in Orissa.
[Illustration: Fig. 16.--Spicules of _Spongilla crassissima_ var.
_crassior_ (from type specimen), × 240.]
BIOLOGY.--_S. crassissima_ is usually found near the surface in shallow
water. Attached to the roots of the floating water-plant _Pistia
stratiotes_ it assumes a spherical form, while on sticks or like objects
it is spindle-shaped. Sometimes it is found growing on the same stick or
reed-stem as _S. carteri_, the two species being in close contact and
_S. carteri_ always overlapping _S. crassissima_. The dark colour is due
to minute masses of blackish pigment in the cells of the parenchyma. The
dense structure of the sponge is not favourable to the presence of
_incolæ_, but young colonies of the polyzoon _Plumatella fruticosa_ are
sometimes overgrown by it. Although they may persist for a time by
elongating their tubular zooecia through the substance of the sponge,
they do not in these circumstances reach the same development as when
they are overgrown by the much softer _S. carteri_.
_S. crassissima_ is found during the "rains" and the cold weather. In
Calcutta it attains its maximum size towards the end of the latter
season. In spite of its hard and compact skeleton, the sponge does not
persist from one cold weather to another.
A curious phenomenon has been noticed in this species, but only in the
case of sponges living in an aquarium, viz. the cessation during the
heat of the day of the currents produced by its flagella.
Subgenus C. STRATOSPONGILLA, _Annandale_.
_Stratospongilla_, Annandale, Zool. Jahrb., Syst. xxvii, p.
561 (1909).
TYPE, _Spongilla bombayensis_, Carter.
Spongillæ in the gemmules of which the pneumatic layer is absent or
irregularly developed, its place being sometimes taken by air-spaces
between the stout chitinous membranes that cover the gemmule. At least
one of these membranes is always present.
The gemmule-spicules lie in the membrane or membranes parallel to the
surface of the gemmule, and are often so arranged as to resemble a
mosaic. The gemmules themselves are usually adherent to the support of
the sponge. The chitinous membrane or membranes are often in continuity
with a membrane that underlies the base of the sponge. The skeleton is
usually stout, though often almost amorphous, and the skeleton-spicules
are sometimes sausage-shaped.
Sponges of this subgenus form crusts or sheets on solid submerged
objects.
_Stratospongilla_ is essentially a tropical subgenus, having its
head-quarters in Central Africa and Western India. One of its species,
however, (_S. sumatrana_*, Weber) occurs both in Africa and the Malay
Archipelago, while another has only been found in S. America (_S.
navicella_, Carter).
Aberrant species occur in China (_S. sinensis_*, _S. coggini_*) and the
Philippines (_S. clementis_*). Three species have been found in the
Bombay Presidency and Travancore, one of which (_S. bombayensis_*)
extends its range eastwards to Mysore and westwards across the Indian
Ocean to Natal.
12. Spongilla indica*, _Annandale_.
_Spongilla indica_, Annandale, Rec. Ind. Mus. ii, p. 25,
figs. 1, 2 (1908).
_Sponge_ forming a very thin layer, of a bright green or pale grey
colour; surface smooth, minutely hispid; pores and oscula inconspicuous,
the latter approached in some instances by radiating furrows; subdermal
cavity small; texture compact, rather hard.
_Skeleton_ incoherent, somewhat massive owing to the large number of
spicules present. Spicules forming triangular meshes and occasionally
arranged in vertical lines several spicules broad but without spongin.
_Spicules._ Skeleton-spicules straight or nearly straight, slender,
cylindrical, amphistrongylous, uniformly covered with minute, sharp
spines; flesh-spicules slender, sharply pointed, straight or curved,
irregularly covered with relatively long, straight sharp spines,
abundant in the dermal membrane, scarce in the substance of the sponge.
Gemmule-spicules short, stout, sausage-shaped, covered with minute
spines, which are sometimes absent from the extremities.
_Gemmules_ spherical, somewhat variable in size, with a single aperture,
which is provided with a trumpet-shaped foraminal tubule and is situated
at one side of the gemmule in its natural position; the inner chitinous
coat devoid of spicules, closely covered by an outer coat composed of a
darkly coloured chitinoid substance in which the gemmule-spicules are
embedded, lying parallel or almost parallel to the inner coat. The outer
coat forms a kind of mantle by means of the skirts of which the gemmule
is fastened to the support of the sponge. This coat is pierced by the
foraminal tubule. The gemmules are distinct from one another.
[Illustration: Fig. 17.--Gemmule of _Spongilla indica_ seen from the
side (from type specimen), magnified.]
Average length of skeleton-spicules 0.2046 mm.
" breadth of skeleton-spicules 0.0172 "
" length of flesh-spicules 0.053 "
" breadth of flesh-spicules 0.0053 "
" length of gemmule-spicules 0.044 "
" breadth of gemmule-spicules 0.0079 "
_S. indica_ is closely allied to _S. sumatrana_*, Weber, which has been
found both in the Malay Archipelago and in East Africa. It may be
distinguished by its blunt, almost truncated megascleres and
comparatively slender gemmule-spicules.
TYPE in the Indian Museum.
HABITAT, etc.--Growing, together with _S. cinerea_ and _Corvospongilla
lapidosa_, on the stone sides of an artificial conduit in the R.
Godaveri at Nasik on the eastern side of the Western Ghats in the Bombay
Presidency. The water was extremely dirty and was used for bathing
purposes. The sponge was green where the light fell upon it, grey where
it was in the shadow of the bridge under which the conduit ran. The only
specimens I have seen were taken in November, 1907.
13. Spongilla bombayensis*, _Carter_. (Plate II, fig. 2.)
_Spongilla bombayensis_, Carter, Ann. Nat. Hist. (5) x, p.
369, pl. xvi, figs. 1-6 (1882).
_Spongilla bombayensis_, Annandale, Zool. Jahrb., Syst.
xxvii, p. 562, figs. B, C (1909).
_Sponge_ hard but friable, forming thin layers or cushions; its surface
often irregular but without a trace of branches; its area never very
great; oscula inconspicuous; external membrane adhering closely to the
sponge; colour brownish or greyish.
[Illustration: Fig. 18.--Gemmule of _Spongilla bombayensis_ as seen from
above (from type specimen), magnified.]
_Skeleton_ almost amorphous, very dense, consisting of large numbers of
spicules arranged irregularly; radiating fibres occasionally visible in
sections, but almost devoid of spongin; a more or less definite
reticulation of horizontal spicules lying immediately under the external
membrane.
_Spicules._ Skeleton-spicules slender, pointed, feebly curved,
irregularly roughened or minutely spined all over the surface.
Flesh-spicules straight, narrowly rhomboidal in outline, sharply
pointed, slender, covered with minute, irregular, straight spines,
scanty in the parenchyma, abundant in the external membrane.
Gemmule-spicules sausage-shaped or bluntly pointed, variable in length
but usually rather stout, covered with minute spines, as a rule
distinctly curved.
_Gemmules_ round or oval, firmly adherent[AH] to the base of the sponge,
as a rule rather shallowly dome-shaped, covered by two thick chitinous
membranes, in each of which there is a dense horizontal layer of
spicules; no granular or cellular covering; the two chitinous coats
separated by an empty space; the aperture or apertures on the side of
the gemmule in its natural position, provided with foraminal tubules,
which may be either straight or curved, project through the outer
chitinous membrane and often bend down towards the base of the gemmule.
The spicules of the outer layer often more irregular in outline and less
blunt than those of the inner layer.
[Footnote AH: The outer covering by means of which the
gemmule is fixed is not formed until the other structures
are complete. In young sponges, therefore, free gemmules may
often be found.]
This sponge is allied to _S. indica_, but is distinguished among other
characters by its sharp skeleton-spicules and by the fact that the
gemmule is covered by two chitinous membranes instead of one.
TYPE in the British Museum; a fragment in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--S. and W. India and S. Africa. Carter's type
was found in the island of Bombay, my own specimens in Igatpuri Lake in
the Western Ghats. I have recently (October 1910) found sponges and bare
gemmules attached to stones at the end of a tank about 10 miles from
Bangalore (Mysore State) in the centre of the Madras Presidency. Prof.
Max Weber obtained specimens in Natal.
BIOLOGY.--The specimens collected by Prof. Weber in Natal and those
collected by myself in the Bombay Presidency were both obtained in the
month of November. It is therefore very interesting to compare them from
a biological point of view. In so doing, it must be remembered that
while in S. Africa November is near the beginning of summer, in India it
is at the beginning of the "cold weather," that is to say, both the
coolest and the driest season of the year. The lake in which my
specimens were obtained had, at the time when they were collected,
already sunk some inches below its highest level, leaving bare a gently
sloping bank of small stones. Adhering to the lower surface of these
stones I found many small patches of _Spongilla bombayensis_, quite dry
but complete so far as their harder parts were concerned and with the
gemmules fully formed at their base. From the shallow water at the edge
of the lake I took many similar stones which still remained submerged.
It was evident that the sponge had been just as abundant on their lower
surface as on that of the stones which were now dry; but only the
gemmules remained, sometimes with a few skeleton-spicules adhering to
them (Pl. II, fig. 2). The bulk of the skeleton had fallen away and the
parenchyma had wholly perished. In a few instances a small sponge, one
or two millimetres in diameter, had already been formed among the
gemmules; but these young sponges appeared to belong to some other
species, possibly _Spongilla indica_, which was also common in the lake.
Carter's specimen of _S. bombayensis_, which was evidently in much the
same condition as those I found still submerged a month later, was taken
in October in a disused quarry. It was surrounded by a mass of _S.
carteri_ three inches in diameter, and was attached to a herbaceous
annual. The point on the edge of the quarry at which this plant grew was
not reached by the water until July. It is therefore necessary to assume
that the gemmules of _S. bombayensis_ had been formed between July and
October. Probably the larva of the sponge had settled down on the plant
during the "rains"--which commence in Bombay about the beginning of
June--and had grown rapidly. The production of gemmules may have been
brought about owing to the sponge being choked by the more vigorous
growth of _S. carteri_, a species which grows to a considerable size in
a comparatively short time, while _S. bombayensis_ apparently never
reaches a thickness of more than a few millimetres.
The manner in which the gemmules of _S. bombayensis_ are fastened to the
solid support of the sponge must be particularly useful in enabling them
to sprout in a convenient environment as soon as the water reaches them.
The fact that the gemmules remained fixed without support renders it
unnecessary for the skeleton to persist as a cage containing them (or at
any rate a proportion of them) during the period of rest.
Prof. Weber's specimens of _S. bombayensis_ were collected in a river,
apparently on stones or rocks, towards the beginning of the S. African
summer. They contain comparatively few gemmules and were evidently in a
vigorous condition as regards vegetative growth. Unfortunately we know
nothing of the seasonal changes which take place in freshwater sponges
in S. Africa, but the difference between these changes in Europe and in
India shows that they are dependent on environment as well as the
idiosyncrasy of the species. It is very interesting, therefore, to see
that the condition of sponges taken in S. Africa differs so widely from
that of other individuals of the same species taken in India at the same
season.
In Prof. Weber's specimens I have found numerous small tubules of
inorganic débris. These appear to be the work of Chironomid larvæ, of
which there are several specimens loose in the bottle containing the
sponges. Other tubules of a very similar appearance but with a delicate
chitinoid foundation appear to be the remains of a species of
_Plumatella_ of which they occasionally contain a statoblast.
14. Spongilla ultima*, _Annandale_. (Plate II, fig. 3.)
_Spongilla ultima_, Annandale, Rec. Ind. Mus. v, p. 31 (1910).
_Sponge_ hard and strong, forming a thin layer on solid objects, of a
pale green colour (dry); the oscula small but rendered conspicuous by
the deep radiating furrows that surround them; external surface of the
sponge rough but not spiny.
_Skeleton_ forming a compact but somewhat irregular reticulation in
which the radiating fibres are not very much more distinct than the
transverse ones; a considerable amount of almost colourless spongin
present.
_Spicules._ Skeleton-spicules smooth, stout, amphioxous, as a rule
straight or nearly straight, not infrequently inflated in the middle or
otherwise irregular. No flesh-spicules. Gemmule-spicules variable in
size, belonging to practically every type and exhibiting practically
every abnormality possible in the genus, the majority being more or less
sausage-shaped and having a roughened surface, but others being
cruciform, spherical, subspherical, rosette-like, needle-like, bifid or
even trifid at one extremity.
[Illustration: Fig. 19.--Spicules of _Spongilla ultima_ (from type
specimen), × 120.]
_Gemmules_ adherent, spherical, large, each covered by two distinct
layers of horizontal spicules; the outer layer intermixed with
skeleton-spicules and often containing relatively large siliceous
spheres, a large proportion of the spicules being irregular in shape;
the spicules of the inner layer much more regular and as a rule
sausage-shaped. The outer layer is contained in a chitinous membrane
which spreads out over the base of the sponge. The foraminal tubules are
short and straight.
This sponge is allied to _S. bombayensis_, from which it is
distinguished not only by the abnormal characters of its
gemmule-spicules and the absence of flesh-spicules, but also by the form
of its skeleton-spicules and the structure of its skeleton. I have
examined several specimens dry and in spirit; but _S. ultima_ is the
only Indian freshwater sponge, except _Corvospongilla burmanica_, I have
not seen in a fresh condition.
TYPES in the Indian Museum; co-types at Trivandrum.
HABITAT. Discovered by Mr. R. Shunkara Narayana Pillay, of the
Trivandrum Museum, in a tank near Cape Comorin, the southernmost point
of the Indian Peninsula.
Genus 2. PECTISPONGILLA, _Annandale_.
_Pectispongilla_, Annandale, Rec. Ind. Mus. iii, p. 103 (1909).
TYPE, _Pectispongilla aurea_, Annandale.
The structure of the sponge resembling that of _Euspongilla_ or
_Ephydatia_; but the gemmule-spicules bear at either end, at one side
only, a double vertical row of spines, so that they appear when viewed
in profile like a couple of combs joined together by a smooth bar.
[Illustration: Fig. 20.--Gemmule and spicules of _Pectispongilla aurea_
(type specimen). _a_, Skeleton-spicules; _b_, gemmule-spicules; _b'_, a
single gemmule-spicule more highly magnified.]
GEOGRAPHICAL DISTRIBUTION.--The genus is monotypic and is only known
from Travancore and Cochin in the south-west of the Indian Peninsula.
15. Pectispongilla aurea*, _Annandale_.
_Pectispongilla aurea_, Annandale, _op. cit._, p. 103, pl.
xii, fig. 2.
_Sponge_ forming minute, soft, cushion-like masses of a deep golden
colour (dull yellow in spirit); the surface smooth, minutely hispid. One
relatively large depressed osculum usually present in each sponge; pores
inconspicuous; dermal membrane in close contact with the parenchyma.
_Skeleton_ consisting of slender and feebly coherent radiating fibres as
a rule two or three spicules thick, with single spicules or ill-defined
transverse fibres running horizontally. Towards the external surface
transverse spicules are numerous, but they do not form any very regular
structure.
_Spicules._ Skeleton-spicules smooth, sharply pointed, straight or
nearly so. Gemmule-spicules minute, with the stem smooth and
cylindrical, relatively stout and much longer than the comb at either
end; the two combs equal, with a number of minute, irregularly scattered
spines between the two outer rows of stouter ones. No free microscleres.
_Gemmules_ minute, spherical, with a single aperture, which is provided
with a very short foraminal tubule; the granular coat well developed;
the spicules arranged in a slanting position, but more nearly vertically
than horizontally, with the combs pointing in all directions; no
external chitinous membrane.
Length of skeleton-spicule 0.2859 mm.
Greatest diameter of skeleton-spicule 0.014 "
Length of gemmule-spicule 0.032-0.036 mm.
Length of comb of gemmule-spicule 0.008 mm.
Greatest diameter of shaft of gemmule-spicule 0.004 "
Diameter of gemmule 0.204-0.221 mm.
The gemmule-spicules first appear as minute, smooth, needle-like bodies,
which later become roughened on one side at either end and so finally
assume the mature form. There are no bubble-cells in the parenchyma.
15_a._ Var. subspinosa*, nov.
This variety differs from the typical form in having its skeleton
spicules covered with minute irregular spines or conical projections.
TYPES of both the typical form and the variety in the Indian Museum;
co-types of the typical form in the Trivandrum Museum.
GEOGRAPHICAL DISTRIBUTION.--The same as that of the genus.
_Localities_:--Tenmalai, at the base of the western slopes of the W.
Ghats in Travancore (typical form) (_Annandale_); Ernakulam and Trichur
in Cochin (var. _subspinosa_) (_G. Mathai_).
BIOLOGY.--My specimens, which were taken in November, were growing on
the roots of trees at the edge of an artificial pool by the roadside.
They were in rather dense shade, but their brilliant golden colour made
them conspicuous objects in spite of their small size. Mr. Mathai's
specimens from Cochin were attached to water-weeds and to the husk of a
cocoanut that had fallen or been thrown into the water.
Genus 3. EPHYDATIA, _Lamouroux_.
_Ephydatia_, Lamouroux, Hist. des Polyp. corall. flex.* p. 6
(_fide_ Weltner) (1816).
_Ephydatia_, J. E. Gray, P. Zool. Soc. London. 1867, p. 550.
_Trachyspongilla_, Dybowsky (_partim_), Zool. Anz. i, p. 53
(1874).
_Meyenia_, Carter (_partim_), Ann. Nat. Hist. (5) vii, p. 90
(1881).
_Carterella_, Potts & Mills (_partim_), P. Ac. Philad. 1881,
p. 150.
_Ephydatia_, Vejdovsky, Abh. Böhm. Ges. xii, p. 23 (1883).
_Meyenia_, Potts (_partim_), _ibid._ 1887, p. 210.
_Carterella_, _id._ (_partim_), _ibid._ 1887, p. 260.
_Ephydatia_, Weltner (_partim_), Arch. Naturg. lxi (i), p.
121 (1895).
_Ephydatia_, Annandale, P. U.S. Mus. xxxvii, p. 404 (1909).
TYPE, (?) _Spongilla fluviatilis_, auctorum.
This genus is separated from _Spongilla_ by the structure of the
gemmule-spicules, which bear at either end a transverse disk with
serrated or deeply notched edges, or at any rate with edges that are
distinctly undulated. The disks are equal and similar. True
flesh-spicules are usually absent, but more or less perfect birotulates
exactly similar to those associated with the gemmules are often found
free in the parenchyma. The skeleton is never very stout and the
skeleton-spicules are usually slender.
As has been already stated, some authors consider _Ephydatia_ as the
type-genus of a subfamily distinguished from the subfamily of which
_Spongilla_ is the type-genus by having rotulate gemmule-spicules. The
transition between the two genera, however, is a very easy one. Many
species of the subgenus _Euspongilla_, the typical subgenus of
_Spongilla_ (including _S. lacustris_, the type-species of the genus),
have the spines at the ends of the gemmule-spicules arranged in such a
way as to suggest rudimentary rotules, while in the typical form of _S.
crateriformis_ this formation is so distinct that the species has
hitherto been placed in the genus _Ephydatia_ (_Meyenia_), although in
some sponges that agree otherwise with the typical form of the species
the gemmule-spicules are certainly not rotulate and in none do these
spicules bear definite disks.
GEOGRAPHICAL DISTRIBUTION.--_Ephydatia_, except _Spongilla_, is the most
generally distributed genus of the Spongillidæ, but in most countries it
is not prolific in species. In Japan, however, it appears to predominate
over _Spongilla_. Only one species is known from India, but another (_E.
blembingia_*, Evans) has been described from the Malay Peninsula, while
Weber found both the Indian species and a third (_E. bogorensis_*) in
the Malay Archipelago.
16. Ephydatia meyeni* (_Carter_).
_Spongilla meyeni_, Carter, J. Bomb. Asiat. Soc. iii, p. 33,
pl. i, fig. 1, & Ann. Nat. Hist. (2) iv, p. 84, pl. iii,
fig. 1 (1849).
_Spongilla meyeni_, Bowerbank, P. Zool. Soc. London, 1863,
p. 448, pl. xxxviii, fig. 4.
_Spongilla meyeni_, Carter, Ann. Nat. Hist. (5) vii, p. 93
(1881).
_Ephydatia fluviatilis_, Weber, Zool. Ergeb. Niederländ.
Ost-Ind. i. pp. 32, 46 (1890).
_Ephydatia mülleri_, Weltner (_partim_), Arch. Naturg. lxi
(i), p. 125 (1895).
_Ephydatia robusta_, Annandale, J. Asiat. Soc. Bengal, 1907,
p. 24, fig. 7.
_Ephydatia mülleri_ subsp. _meyeni_, _id._, Rec. Ind. Mus.
ii, p. 306 (1908).
_Sponge_ hard and firm but easily torn, usually of a clear white,
sometimes tinged with green, forming irregular sheets or masses never of
great thickness, without branches but often with stout subquadrate
projections, the summits of which are marked with radiating grooves; the
whole surface often irregularly nodulose and deeply pitted; the oscula
inconspicuous; the membrane adhering closely to the parenchyma. _The
parenchyma contains numerous bubble-cells_ (see p. 31, fig. 2).
_Skeleton_ dense but by no means regular; the radiating fibres distinct
and containing a considerable amount of spongin, at any rate in the
outer part of the sponge; transverse fibres hardly distinguishable,
single spicules and irregular bundles of spicules taking their place.
[Illustration: Fig. 21.--Gemmule and spicules of _Ephydatia meyeni_
(from Calcutta). _a_, Skeleton-spicules; _b_, gemmule-spicules.]
_Spicules._ Skeleton-spicules entirely smooth, moderately stout, feebly
curved, sharply pointed. No flesh-spicules. Gemmule-spicules with the
shaft as a rule moderately stout, much longer than the diameter of one
disk, smooth or with a few stout, straight horizontal spines, which are
frequently bifid or trifid; the disks flat, of considerable size, with
their margins cleanly and deeply divided into a comparatively small
number of deep, slender, triangular processes of different sizes; the
shaft extending not at all or very little beyond the disks.
_Gemmules_ spherical, usually numerous and of rather large size; each
covered by a thick layer of minute air-spaces, among which the
gemmule-spicules are arranged vertically, often in two or even three
concentric series; a single short foraminal tubule; the pneumatic coat
confined externally by a delicate membrane, with small funnel-shaped
pits over the spicules of the outer series.
I think that the gemmules found by me in Bhim Tal and assigned to
Potts's _Meyenia robusta_ belong to this species, but some of the
spicules are barely as long as the diameter of the disks. In any case
Potts's description is so short that the status of his species is
doubtful. His specimens were from N. America.
_E. meyeni_ is closely related to the two commonest Holarctic species of
the genus, _E. fluviatilis_ and _E. mülleri_, which have been confused
by several authors including Potts. From _E. fluviatilis_ it is
distinguished by the possession of bubble-cells in the parenchyma, and
from _E. mülleri_ by its invariably smooth skeleton-spicules and the
relatively long shafts of its gemmule-spicules. The latter character is
a marked feature of the specimens from the Malay Archipelago assigned by
Prof. Max Weber to _E. fluviatilis_; I am indebted to his kindness for
an opportunity of examining some of them.
TYPE in the British Museum; a fragment in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--India and Sumatra. _Localities_:--BENGAL,
Calcutta and neighbourhood (_Annandale_); MADRAS PRESIDENCY, Cape
Comorin, Travancore (_Trivandrum Mus._): BOMBAY PRESIDENCY, Island of
Bombay (_Carter_): HIMALAYAS, Bhim Tal, Kumaon (alt. 4,500 feet)
(_Annandale_).
BIOLOGY.--My experience agrees with Carter's, that this species is never
found on floating objects but always on stones or brickwork. It grows in
the Calcutta "tanks" on artificial stonework at the edge of the water,
together with _Spongilla carteri_, _S. alba_, _S. fragilis_ subsp.
_calcuttana_, and _Trochospongilla latouchiana_. It flourishes during
the cold weather and often occupies the same position in succeeding
years. In this event the sponge usually consists of a dead base, which
is of a dark brownish colour and contains no cells, and a living upper
layer of a whitish colour.
The larva of _Sisyra indica_ is sometimes found in the canals, but the
close texture of the sponge does not encourage the visits of other
_incolæ_.
Genus 4. DOSILIA, _Gray_.
_Dosilia_, J. E. Gray, P. Zool. Soc. London, 1867, p. 550.
TYPE, _Spongilla plumosa_, Carter.
This genus is distinguished from _Ephydatia_ by the nature of the free
microscleres, the microscleres of the gemmule being similar in the two
genera. The free microscleres consist as a rule of several or many
shafts meeting together in several or many planes at a common centre,
which is usually nodular. The free ends of these shafts often possess
rudimentary rotulæ. Occasionally a free microsclere may be found that is
a true monaxon and sometimes such spicules are more or less distinctly
birotulate. The skeleton is also characteristic. It consists mainly of
radiating fibres which bifurcate frequently in such a way that a
bush-like structure is produced. Transverse fibres are very feebly
developed and are invisible to the naked eye. Owing to the structure of
the skeleton the sponge has a feathery appearance.
Gray originally applied the name _Dosilia_ to this species and to
_"Spongilla" baileyi_, Bowerbank. It is doubtful how far his generic
description applies to the latter, which I have not seen; but although
the position of _"Spongilla" baileyi_ need not be discussed here, I may
say that I do not regard it as a congener of _Dosilia plumosa_, the free
microscleres of which are of a nature rare but not unique in the family.
With _Dosilia plumosa_ we must, in any case, associate in one genus the
two forms that have been described as varieties, viz., _palmeri_*, Potts
from Texas and Mexico, and _brouini_*, Kirkpatrick from the White Nile.
By the kindness of the authorities of the Smithsonian Institution and
the British Museum I have been able to examine specimens of all three
forms, in each case identified by the author of the name, and I am
inclined to regard them as three very closely allied but distinct
species. Species with free microscleres similar to those of these three
forms but with heterogeneous or tubelliform gemmule-spicules will
probably need the creation of a new genus or new genera for their
reception.
GEOGRAPHICAL DISTRIBUTION.--The typical species occurs in Bombay and
Madras; _D. palmeri_ has probably an extensive range in the drier parts
of Mexico and the neighbouring States, while _D. brouini_ has only been
found on the banks of the White Nile above Khartoum, in Tropical Africa.
17. Dosilia plumosa* (_Carter_).
_Spongilla plumosa_, Carter, J. Bomb. Asiat. Soc. iii, p.
34, pl. i, fig. 2, & Ann. Nat. Hist. (2) iv, p. 85, pl. iii,
fig. 2 (1849).
_Spongilla plumosa_, Bowerbank, P. Zool. Soc. London, 1863,
p. 449, pl. xxxviii, fig. 5.
_Dosilia plumosa_, J. E. Gray, _ibid._ 1867, p. 551.
_Meyenia plumosa_, Carter, Ann. Nat. Hist. (5) vii, p. 94,
pl. v, fig. 6 (1881).
_Meyenia plumosa_, Potts, P. Ac. Philad. 1887, p. 233.
_Ephydatia plumosa_, Weltner, Arch. Naturg. lxi (i), p. 126
(1895).
_Ephydatia plumosa_, Petr, Rozp. Ceske Ak. Praze, Trída ii,
pl. ii, figs. 29, 30 (text in Czech) (1899).
_Sponge_ forming soft irregular masses which are sometimes as much as 14
cm. in diameter, of a pale brown or brilliant green colour; no branches
developed but the surface covered with irregular projections usually of
a lobe-like nature.
_Skeleton_ delicate, with the branches diverging widely, exhibiting the
characteristic structure of the genus in a marked degree, containing a
considerable amount of chitin, which renders it resistant in spite of
its delicacy.
_Spicules._ Skeleton-spicules smooth, sharply pointed, nearly straight,
moderately slender, about twenty times as long as their greatest
transverse diameter. Flesh-spicules occasionally amphioxous or
birotulate and with a single shaft, more frequently consisting of many
shafts meeting in a distinct central nodule, which is itself smooth; the
shafts irregularly spiny, usually more or less nodular at the tip, which
often bears a distinct circle of recurved spines that give it a rotulate
appearance. Gemmule-spicules with long, slender, straight shafts, which
bear short, slender, straight, horizontal spines sparsely and
irregularly scattered over their surface; the rotulæ distinctly convex
when seen in profile; their edge irregularly and by no means deeply
notched; the shafts not extending beyond their surface but clearly seen
from above as circular umbones.
[Illustration: Fig. 22.--_Dosilia plumosa._
A=microscleres, × 240; B=gemmule as seen in optical section from
below, × 75. (From Rambha.)]
_Gemmules._ Somewhat depressed, covered with a thick granular pneumatic
coat, in which the spicules stand erect; the single aperture depressed.
Each gemmule surrounded more or less distinctly by a circle or several
circles of flesh-spicules.
TYPE in the British Museum; some fragments in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--Bombay and Madras. Carter's specimens were
taken in the island of Bombay, mine at Rambha in the north-east of the
Madras Presidency. I have been unable to discover this species in the
neighbourhood of Calcutta, but it is apparently rare wherever it occurs.
BIOLOGY.--Carter writes as regards this species:--"This is the coarsest
and most resistant of all the species. As yet I have only found three or
four specimens of it, and these only in two tanks. I have never seen it
fixed on any solid body, but always floating on the surface of the
water, about a month after the first heavy rains of the S.W. monsoon
have fallen. Having made its appearance in that position, and having
remained there for upwards of a month, it then sinks to the bottom. That
it grows like the rest, adherent to the sides of the tank, must be
inferred from the first specimen which I found (which exceeds two feet
in circumference) having had a free and a fixed surface, the latter
coloured by the red gravel on which it had grown. I have noticed it
growing, for two successive years in the month of July, on the surface
of the water of one of the two tanks in which I have found it, and would
account for its temporary appearance in that position, in the following
way, viz., that soon after the first rains have fallen, and the tanks
have become filled, all the sponges in them appear to undergo a partial
state of putrescency, during which gas is generated in them, and
accumulates in globules in their structure, through which it must burst,
or tear them from their attachments and force them to the surface of the
water. Since then the coarse structure of _plumosa_ would appear to
offer greater resistance to the escape of this air, than that of any of
the other species, it is probable that this is the reason of my having
hitherto only found it in the position mentioned."
It seems to me more probable that the sponges are actually broken away
from their supports by the violence of the rain and retain air
mechanically in their cavities. The only specimens of _D. plumosa_ that
I have seen alive were attached very loosely to their support. In
writing of the "coarse structure" of this species, Carter evidently
alludes to the wide interspaces between the component branches of the
skeleton.
My specimens were attached to the stem of a water-lily growing in a pool
of slightly brackish water and were of a brilliant green colour. I
mistook them at first for specimens of _S. lacustris_ subsp.
_reticulata_ in which the branches had not developed normally. They were
taken in March and were full of gemmules. The pool in which they were
growing had already begun to dry up.
Genus 5. TROCHOSPONGILLA, _Vejdovsky_.
_Trochospongilla_, Vejdovsky, Abh. K. Böhm. Ges. Wiss. xii,
p. 31 (1883).
_Trochospongilla_, Wierzejski, Arch. Slaves de Biologie, i,
p. 44 (1886).
_Trochospongilla_, Vejdovsky, P. Ac. Philad. 1887, p. 176.
_Meyenia_, Potts (_partim_), _ibid._ p. 210.
_Tubella_, _id._ (_partim_), _ibid._, p. 248.
_Meyenia_, Carter (_partim_), Ann. Nat. Hist. (5) vii, p. 90
(1881).
_Trochospongilla_, Weltner, in Zacharias's Tier- und
Pflanzenwelt, i, p. 215 (1891).
_Trochospongilla_, _id._, Arch. Naturg. lxi (i), p. 120
(1895).
_Tubella_, _id._ (_partim_), _ibid._ p. 128.
TYPE, _Spongilla erinaceus_, Ehrenberg.
The characteristic feature of this genus is that the rotulæ of the
gemmule-spicules, which are homogeneous, have smooth instead of serrated
edges. Their stem is always short and they are usually embedded in a
granular pneumatic coat. The sponge is small in most of the species as
yet known; in some species microscleres without rotulæ are associated
with the gemmules.
[Illustration: Fig. 23.--A=skeleton-spicule of _Trochospongilla
latouchiana_; A'=gemmule-spicule of the same species; B=gemmule of _T.
phillottiana_ as seen in optical section from above; B'=skeleton-spicule
of same species: A, A', B' × 240; B × 75. All specimens from Calcutta.]
I think it best to include in this genus, as the original diagnosis
would suggest, all those species in which all the gemmule-spicules are
definitely birotulate and have smooth edges to their disks, confining
the name _Tubella_ to those in which the upper rotula is reduced to a
mere knob. Even in those species in which the two disks are normally
equal, individual spicules may be found in which the equality is only
approximate, while, on the other hand, it is by no means uncommon for
individual spicules in such species as _"Tubella" pennsylvanica_, which
is here included in _Trochospongilla_, to have the two disks nearly
equal, although normally the upper one is much smaller than the lower.
There is very rarely any difficulty, however, in seeing at a glance
whether the edge of the disk is smooth or serrated, the only species in
which this difficulty would arise being, so far as I am aware, the
Australian _Ephydatia capewelli_* (Haswell), the disks of which are
undulated and nodulose rather than serrated.
GEOGRAPHICAL DISTRIBUTION.--The genus includes so large a proportion of
small, inconspicuous species that its distribution is probably known but
imperfectly. It would seem to have its headquarters in N. America but
also occurs in Europe and Asia. In India three species have been found,
one of which (_T. pennsylvanica_) has an extraordinarily wide and
apparently discontinuous range, being common in N. America, and having
been found in the west of Ireland, the Inner Hebrides, and near the west
coast of S. India. The other two Indian species are apparently of not
uncommon occurrence in eastern India and Burma.
_Key to the Indian Species of_ Trochospongilla.
I. Rotules of the gemmule-spicules equal
or nearly so.
A. Skeleton-spicules smooth, usually
pointed _latouchiana_, p. 115.
B. Skeleton-spicules spiny, blunt _phillottiana_, p. 117.
II. Upper rotule of the gemmule-spicules
distinctly smaller than the lower.
Skeleton-spicules spiny, pointed _pennsylvanica_, p. 118.
18. Trochospongilla latouchiana*, _Annandale_.
_Trochospongilla latouchiana_, Annandale, J. Asiat. Soc.
Bengal, 1907, p. 21, fig. 5.
_Trochospongilla latouchiana_, _id._, Rec. Ind. Mus. ii, p.
157 (1908).
_Trochospongilla leidyi_, _id._ (_nec_ Bowerbank), _ibid._
iii, p. 103 (1909).
[Illustration: Fig. 24.--_Trochospongilla latouchiana._
Vertical section of part of skeleton with gemmules _in situ_, × 30; also
a single gemmule, × 70. (From Calcutta).]
_Sponge_ forming cushion-shaped masses rarely more than a few
centimetres in diameter or thickness and of a brown or yellow colour,
hard but rather brittle; surface evenly rounded, minutely hispid; oscula
inconspicuous, small, circular, depressed, very few in number; external
membrane adhering closely to the parenchyma; a chitinous membrane at the
base of the sponge. Larger sponges divided into several layers by
similar membranes.
_Skeleton_ dense, forming a close reticulation; radiating fibres slender
but quite distinct, running up right through the sponge, crossed at
frequent intervals by single spicules or groups of spicules.
_Spicules._ Skeleton-spicules smooth, about twenty times as long as the
greatest transverse diameter, as a rule sharply pointed; smooth
amphistrongyli, which are often inflated in the middle, sometimes mixed
with them but never in large numbers. No flesh-spicules.
Gemmule-spicules with the rotulæ circular or slightly asymmetrical, flat
or nearly flat, marked with a distinct double circle as seen from above,
sometimes not quite equal; the shaft not projecting beyond them; the
diameter of the rotule 4-1/2 to 5 times that of the shaft, which is
about 2-2/3 times as long as broad.
_Gemmules_ small (0.2 × 0.18 mm.), as a rule very numerous and scattered
throughout the sponge, flask-shaped, clothed when mature with a thin
microcell coat in which the birotulates are arranged with overlapping
rotulæ, their outer rotulæ level with the surface; foraminal aperture
circular, situated on an eminence.
_Average Measurements._
Diameter of gemmule 0.2 × 0.18 mm.
Length of skeleton-spicule 0.28 "
Length of birotulate-spicule 0.175 "
Diameter of rotula 0.02 "
_T. latouchiana_ is closely related to _T. leidyi_ (Bowerbank) from N.
America, but is distinguished by its much more slender
skeleton-spicules, by the fact that the gemmules are not enclosed in
cages of megascleres or confined to the base of the sponge, and by
differences in the structure of the skeleton.
TYPE in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--Lower Bengal and Lower Burma.
_Localities_:--BENGAL, Calcutta and neighbourhood (_Annandale_): BURMA,
Kawkareik, Amherst district, Tenasserim (_Annandale_).
BIOLOGY.--This species, which is common in the Museum tank, Calcutta, is
apparently one of those that can grow at any time of year, provided that
it is well covered with water. Like _T. leidyi_ it is capable of
producing fresh layers of living sponge on the top of old ones, from
which they are separated by a chitinous membrane. These layers are not,
however, necessarily produced in different seasons, for it is often
clear from the nature of the object to which the sponge is attached that
they must all have been produced in a short space of time. What appears
to happen in most cases is this:--A young sponge grows on a brick, the
stem of a reed or some other object at or near the edge of a pond, the
water in which commences to dry up. As the sponge becomes desiccated its
cells perish. Its gemmules are, however, retained in the close-meshed
skeleton, which persists without change of form. A heavy shower of rain
then falls, and the water rises again over the dried sponge. The
gemmules germinate immediately and their contents spread out over the
old skeleton, secrete a chitinous membrane and begin to build up a new
sponge. The process may be repeated several times at the change of the
seasons or even during the hot weather, or after a "break in the rains."
If, however, the dried sponge remains exposed to wind and rain for more
than a few months, it begins to disintegrate and its gemmules are
carried away to other places. Owing to their thin pneumatic coat and
relatively heavy spicules they are not very buoyant. Even in the most
favourable circumstances the sponge of _T. latouchiana_ never forms
sheets of great area. In spite of its rapid growth it is frequently
overgrown by _Spongilla carteri_.
19. Trochospongilla phillottiana*, _Annandale_.
_Trochospongilla phillottiana_, Annandale, J. Asiat. Soc.
Bengal, 1907, p. 22, fig. 6.
_Trochospongilla phillottiana_, _id._, Rec. Ind. Mus. i, p.
269 (1907).
_Trochospongilla phillottiana_, _id._, _ibid._ ii, p. 157
(1908).
_Sponge_ hard but friable, forming sheets or patches often of great
extent but never more than about 5 mm. thick; the surface minutely
hispid, flat; colour pale yellow, the golden-yellow gemmules shining
through the sponge in a very conspicuous manner; oscula inconspicuous;
external membrane adherent; no basal chitinous membrane.
_Skeleton_ dense but by no means strong; the reticulation close but
produced mainly by single spicules, which form triangular meshes;
radiating fibres never very distinct, only persisting for a short
distance in a vertical direction; each gemmule enclosed in an open,
irregular cage of skeleton-spicules.
_Spicules._ Skeleton-spicules short, slender, blunt, more or less
regularly and strongly spiny, straight or feebly curved. No
flesh-spicules. Gemmule-spicules with the rotulæ circular, very wide as
compared with the shaft, concave on the surface, with the shaft
projecting as an umbo on the surface; the lower rotula often a little
larger than the upper.
_Gemmules_ numerous, situated at the base of the sponge in irregular,
one-layered patches, small (0.32 × 0.264 mm.), of a brilliant golden
colour, distinctly wider than high, with a single aperture situated on
an eminence on the apex, each clothed (when mature) with a pneumatic
coat that contains relatively large but irregular air-spaces among which
the spicules stand with the rotulæ overlapping alternately, a
funnel-shaped pit in the coat descending from the surface to the upper
rotula of each of them; the surface of the gemmule covered with
irregular projections.
Diameter of gemmule 0.32 × 0.264 mm.
Length of skeleton-spicule 0.177 "
Length of gemmule-spicule 0.015 "
Diameter of rotule 0.022 "
This species appears to be related to _T. pennsylvanica_, from which it
differs mainly in the form of its gemmule-spicules and the structure of
its gemmule. My original description was based on specimens in which the
gemmule-spicules were not quite mature.
TYPE in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--Lower Bengal and Lower Burma.
_Localities_:--BENGAL, Calcutta (_Annandale_): BURMA, jungle pool near
Kawkareik, Amherst district, Tenasserim (_Annandale_).
BIOLOGY.--This species covers a brick wall at the edge of the Museum
tank in Calcutta every year during the "rains." In the cold weather the
wall is left dry, but it is usually submerged to a depth of several feet
before the middle of July. It is then rapidly covered by a thin layer of
the sponge, which dies down as soon as the water begins to sink when the
"rains" are over. For some months the gemmules adhere to the wall on
account of the cage of spicules in which each of them is enclosed, but
long before the water rises again the cages disintegrate and the
gemmules are set free. Many of them fall or are carried by the wind into
the water, on the surface of which, owing to their thick pneumatic coat,
they float buoyantly. Others are lodged in cavities in the wall. On the
water the force of gravity attracts them to one another and to the edge
of the pond, and as the water rises they are carried against the wall
and germinate. In thick jungle at the base of the Dawna Hills near
Kawkareik[AI] in the interior of Tenasserim, I found the leaves of
shrubs which grew round a small pool, covered with little dry patches of
the sponge, which had evidently grown upon them when the bushes were
submerged. This was in March, during an unusually severe drought.
[Footnote AI: This locality is often referred to in
zoological literature as Kawkare_et_ or Kawkari_t_, or even
K_o_kari_t_.]
20. Trochospongilla pennsylvanica* (_Potts_).
_Tubella pennsylvanica_, Potts, P. Ac. Philad. 1882, p. 14.
_Tubella pennsylvanica_, _id._, _ibid._ 1887, p. 251, pl.
vi, fig. 2, pl. xii, figs. 1-3.
_Tubella pennsylvanica_, Mackay, Trans. Roy. Soc. Canada,
1889, Sec. iv, p. 95.
_Tubella pennsylvanica_, Hanitsch, Nature, li, p. 511
(1895).
_Tubella pennsylvanica_, Weltner, Arch. Naturg. lxi (i), p.
128 (1895).
_Tubella pennsylvanica_, Hanitsch, Irish Natural. iv, p. 129
(1895).
_Tubella pennsylvanica_, Annandale, J. Linn. Soc., Zool.,
xxx, p. 248 (1908).
_Tubella pennsylvanica_, _id._, Rec. Ind. Mus. iii, p. 102
(1909).
_Tubella_ _pennsylvanica_, _id._, P. U.S. Mus. xxxvii, p.
403, fig. 2 (1909).
_Sponge_ soft, fragile, forming small cushion-shaped masses, grey or
green; oscula few in number, often raised on sloping eminences
surrounded by radiating furrows below the external membrane; external
membrane adhering to the parenchyma.
_Skeleton_ close, almost structureless. "Surface of mature specimens
often found covered with parallel skeleton spicules, not yet arranged to
form cell-like interspaces" (_Potts_).
_Spicules._ Skeleton-spicules slender, cylindrical, almost straight,
sharp or blunt, minutely, uniformly or almost uniformly spined; spines
sometimes absent at the tips. No flesh-spicules. Gemmule-spicules with
the lower rotula invariably larger than the upper; both rotulæ flat or
somewhat sinuous in profile, usually circular but sometimes asymmetrical
or subquadrate in outline, varying considerably in size.
_Gemmules_ small, numerous or altogether absent, covered with a granular
pneumatic coat of variable thickness; the rotulæ of the gemmule-spicules
overlapping and sometimes projecting out of the granular coat.
The measurements of the spicules and gemmules of an Indian specimen and
of one from Lehigh Gap, Pennsylvania, are given for comparison:--
Travancore. Pennsylvania.
Length of skeleton-spicules 0.189-0.242 mm. 0.16-0.21 mm.
(average 0.205 mm.) (average 0.195 mm.)
Breadth " " 0.0084-0.0155 mm. 0.0084 mm.
Length of birotulate 0.0126 " 0.0099 "
Diameter of upper rotula 0.0084 " 0.0084 "
" lower " 0.0169 " 0.0168 "
" gemmule 0.243-0.348 mm. 0.174-0.435 mm.
The spicules of the Travancore specimen are, therefore, a trifle larger
than those of the American one, but the proportions are closely similar.
The difference between the gemmule-spicules of this species and those of
such a form as _T. phillottiana_ is merely one of degree and can hardly
be regarded as a sufficient justification for placing the two species in
different genera. If, as I have proposed, we confine the generic name
_Tubella_ to those species in which the gemmule-spicules are really like
"little trumpets," the arrangement is a much more natural one, for these
species have much in common apart from the gemmule-spicules. _T.
pennsylvanica_ does not appear to be very closely related to any other
known species except _T. phillottiana_.
TYPE in the U.S. National Museum, from which specimens that appear to be
co-types have been sent to the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--Very wide and apparently discontinuous:--N.
America (widely distributed), Ireland (_Hanitsch_), Hebrides of Scotland
(_Annandale_), Travancore, S. India (_Annandale_). The only Indian
locality whence I have obtained specimens is Shasthancottah Lake near
Quilon in Travancore.
BIOLOGY.--In Shasthancottah Lake _T. pennsylvanica_ is found on the
roots of water-plants that are matted together to form floating islands.
It appears to avoid light and can only be obtained from roots that have
been pulled out from under the islands. In Scotland I found it on the
lower surface of stones near the edge of Loch Baa, Isle of Mull. In such
circumstances the sponge is of a greyish colour, but specimens of the
variety _minima_ taken by Potts on rocks and boulders in Bear Lake,
Pennsylvania, were of a bright green.
Sponges taken in Travancore in November were full of gemmules; in my
Scottish specimens (taken in October) I can find no traces of these
bodies, but embryos are numerous.
Genus 6. TUBELLA, _Carter_.
_Tubella_, Carter, Ann. Nat. Hist. (5) vii, p. 96 (1881).
_Tubella_, Potts (_partim_), P. Ac. Philad. 1887, p. 248.
_Tubella_, Weltner (_partim_), Arch. Naturg. lxi (i), p. 128
(1895).
TYPE, _Spongilla paulula_, Bowerbank.
This genus is distinguished from _Ephydatia_ and _Trochospongilla_ by
the fact that the two ends of the gemmule-spicules are unlike not only
in size but also in form. It sometimes happens that this unlikeness is
not so marked in some spicules as in others, but in some if not in all
the upper end of the shaft (that is to say the end furthest removed from
the inner coat of the gemmule in the natural position) is reduced to a
rounded knob, while the lower end expands into a flat transverse disk
with a smooth or denticulated edge. The spicule thus resembles a little
trumpet resting on its mouth. The shaft of the spicule is generally
slender and of considerable length. The skeleton of the sponge is as a
rule distinctly reticulate and often hard; the skeleton-spicules are
either slender or stout and sometimes change considerably in proportions
and outline as they approach the gemmules.
GEOGRAPHICAL DISTRIBUTION.--The genus is widely distributed in the
tropics of both Hemispheres, its headquarters apparently being in S.
America; but it is nowhere rich in species. Only two are known from the
Oriental Region, namely _T. vesparium_* from Borneo, and _T.
vesparioides_* from Burma.
21. Tubella vesparioides*, _Annandale_. (Plate II, fig. 4.)
_Tubella vesparioides_, Annandale, Rec. Ind. Mus. ii, p. 157
(1908).
_Sponge_ forming rather thick sheets of considerable size, hard but
brittle, almost black in colour; oscula inconspicuous; external membrane
supported on a reticulate horizontal skeleton.
_Skeleton._ The surface covered with a network of stout spicule-fibres,
the interstices of which are more or less deeply sunk, with sharp fibres
projecting vertically upwards at the nodes; the whole mass pervaded by a
similar network, which is composed of a considerable number of spicules
lying parallel to one another, overlapping at the ends and bound
together by a profuse secretion of spongin.
[Illustration: Fig. 25.--Spicules of _Tubella vesparioides_ (from type
specimen). × 240.]
_Spicules._ Skeleton-spicules slender, smooth, amphioxous, bent in a
wide arc or, not infrequently, at an angle. No true flesh-spicules.
Gemmule-spicules terminating above in a rounded, knob-like structure and
below in a relatively broad, flat rotula, which is very deeply and
irregularly indented round the edge when mature, the spicules at an
earlier stage of development having the form of a sharp pin with a round
head; shaft of adult spicules projecting slightly below the rotula,
long, slender, generally armed with a few stout conical spines, which
stand out at right angles to it.
_Gemmules_ numerous throughout the sponge, spherical, provided with a
short, straight foraminal tubule, surrounded by one row of spicules,
which are embedded in a rather thin granular coat.
Average length of skeleton-spicule 0.316 mm.
" breadth of skeleton-spicule 0.0135 "
" length of gemmule-spicule 0.046 "
" diameter of rotula 0.0162 "
" " gemmule 0.446 "
This sponge is closely related to _Tubella vesparium_ (v. Martens) from
Borneo, from which it may be distinguished by its smooth
skeleton-spicules and the deeply indented disk of its gemmule-spicules.
The skeleton-fibres are also rather less stout. By the kindness of Dr.
Weltner, I have been able to compare types of the two species.
TYPE in the Indian Museum.
HABITAT.--Taken at the edge of the Kanghyi ("great pond") at Mudon near
Moulmein in the Amherst district of Tenasserim. The specimens were
obtained in March in a dry state and had grown on logs and branches
which had evidently been submerged earlier in the year. The name
_vesparium_ given to the allied species on account of its resemblance to
a wasps' nest applies with almost equal force to this Burmese form.
Genus 7. CORVOSPONGILLA, nov.
TYPE[AJ], _Spongilla loricata_, Weltner.
[Footnote AJ: Potts's _Spongilla novæ-terræ_ from
Newfoundland and N. America cannot belong to this genus
although it has similar flesh-spicules, for, as Weltner has
pointed out (_op. cit. supra_ p. 126), the gemmule-spicules
are abortive rotulæ. This is shown very clearly in the
figure published by Petr (Rozp. Ceske Ak. Praze, Trída, ii,
pl. ii, figs. 27, 28, 1899), who assigns the species to
_Heteromeyenia_. Weltner places it in _Ephydatia_, and it
seems to be a connecting link between the two genera. It has
been suggested that it is a hybrid (Traxler, Termes.
Fuzetek, xxi, p. 314, 1898).]
Spongillidæ in which the gemmule-spicules are without a trace of rotulæ
and the flesh-spicules have slender cylindrical shafts that bear at or
near either end a circle of strong recurved spines. The gemmule-spicules
are usually stout and sausage-shaped, and the gemmules resemble those of
_Stratospongilla_ in structure. The skeleton is strong and the
skeleton-spicules stout, both resembling those of the "genus"
_Potamolepis_, Marshall.
As in all other genera of Spongillidæ the structure of the skeleton is
somewhat variable, the spicule-fibres of which it is composed being much
more distinct in some species than in others. The skeleton-spicules are
often very numerous and in some cases the skeleton is so compact and
rigid that the sponge may be described as stony. The flesh-spicules
closely resemble the gemmule-spicules of some species of _Ephydatia_ and
_Heteromeyenia_.
GEOGRAPHICAL DISTRIBUTION.--The species of this genus are probably
confined to Africa (whence at least four are known) and the Oriental
Region. One has been recorded from Burma and another from the Bombay
Presidency.
_Key to the Indian Species of_ Corvospongilla.
I. Gemmule with two layers of gemmule-spicules;
those of the inner layer not
markedly smaller than those of the outer. _burmanica_, p. 123.
II. Gemmule with two layers of gemmule-spicules,
the outer of which contains
spicules of much greater size than the
inner. _lapidosa_, p. 124.
22. Corvospongilla burmanica* (_Kirkpatrick_). (Plate II, fig. 5.)
_Spongilla loricata_ var. _burmanica_, Kirkpatrick, Rec.
Ind. Mus. ii, p. 97, pl. ix (1908).
_Sponge_ forming a shallow sheet, hard, not very strong, of a pale
brownish colour; the surface irregularly spiny; the oscula small but
conspicuous, circular, raised on little turret-like eminences; the
external membrane adhering closely to the sponge.
_Skeleton_ dense but by no means regular; the network composed largely
of single spines; thick radiating fibres distinguishable in the upper
part of the sponge.
_Spicules._ Skeleton-spicules smooth, not very stout, amphistrongylous,
occasionally a little swollen at the ends, often with one or more
fusiform swellings, measuring on an average about 0.27 × 0.0195 mm.
Flesh-spicules with distinct rotules, the recurved spines numbering 4 to
6, measuring about 1/7 the length of the spicules; the shaft by no means
strongly curved; their length from 0.03-0.045 mm. Gemmule-spicules
amphioxous, as a rule distinctly curved, sometimes swollen at the ends,
covered regularly but somewhat sparsely with fine spines, not measuring
more than 0.49 × 0.078 mm.
_Gemmules_ strongly adherent, arranged in small groups, either single or
double; when single spherical, when double oval; each gemmule or pair of
gemmules covered by two layers of gemmule-spicules bound together in
chitinous substance; the inner layer on the inner coat of the gemmule,
the outer one separated from it by a space and in contact with the outer
cage of skeleton-spicules; the size of the gemmule-spicules variable in
both layers; external to the outer layer a dense cage of
skeleton-spicules; foraminal tubule short, cylindrical.
This sponge is closely related to _S. loricata_, Weltner, of which
Kirkpatrick regards it as a variety. "The main difference," he writes,
"between the typical African form and the Burmese variety consists in
the former having much larger microstrongyles (83 × 15.7 µ [0.83 × 0.157
mm.]) with larger and coarser spines;... Judging from Prof. Weltner's
sections of gemmules, these bodies lack the definite outer shell of
smooth macrostrongyles [blunt skeleton-spicules], though this may not
improbably be due to the breaking down and removal of this layer. A
further difference consists in the presence, in the African specimen, of
slender, finely spined strongyles [amphistrongyli], these being absent
in the Burmese form, though perhaps this fact is not of much
importance."
TYPE in the British Museum; a piece in the Indian Museum.
HABITAT.--Myitkyo, head of the Pegu-Sittang canal, Lower Burma (_E. W.
Oates_).
BIOLOGY.--The sponge had grown over a sheet of the polyzoon _Hislopia
lacustris_, Carter (see p. 204), remains of which can be detected on its
lower surface.
"Mr. E. W. Oates, who collected and presented the sponge, writes that
the specimen was found encrusting the vertical and horizontal surfaces
of the bottom beam of a lock gate, where it covered an area of six
square feet. The beam had been tarred several times before the sponge
was discovered. The portion of the gate on which the sponge was growing
was submerged from November to May for eight hours a day at spring
tides, but was entirely dry during the six days of neap tides. From May
to October it was constantly submerged. The sponge was found in April.
Although the canal is subject to the tides, the water at the lock is
always fresh. The colour of the sponge during life was the same as in
its present condition."
23. Corvospongilla lapidosa* (_Annandale_).
_Spongilla lapidosa_ Annandale, Rec. Ind. Mus. ii, pp. 25,
26, figs. 3, 4, 5 (1908).
The _sponge_ forms a thin but extremely hard and resistant crust the
surface of which is either level, slightly concave, or distinctly
corrugated; occasional groups of spicules project from it, but their
arrangement is neither so regular nor so close as is the case in _C.
burmanica_. The dermal membrane adheres closely to the sponge. The
oscula are small; some of them are raised above the general surface but
not on regular turret-shaped eminences. The colour is grey or black.
There is a thick chitinous membrane at the base of the sponge.
[Illustration: Fig. 26.--Spicules of _Corvospongilla lapidosa_ (from
type specimen), × 240.]
The _skeleton_ is extremely dense owing to the large number of spicules
it contains, but almost structureless; broad vertical groups of spicules
occur but lack spongin and only traverse a small part of the thickness
of the sponge; their position is irregular. The firmness of the skeleton
is due almost entirely to the interlocking of individual spicules. At
the base of the sponge the direction of a large proportion of the
spicules is horizontal or nearly horizontal, the number arranged
vertically being much greater in the upper part.
_Spicules._ The skeleton-spicules are sausage-shaped and often a little
swollen at the ends or constricted in the middle. A large proportion are
twisted or bent in various ways, and a few bear irregular projections or
swellings. The majority, however, are quite smooth. Among them a few
more or less slender, smooth amphioxi occur, but these are probably
immature spicules. The length and curvature of the amphistrongyli varies
considerably, but the average measurements are about 0.28 × 0.024 mm.
The flesh-spicules also vary greatly in length and in the degree to
which their shafts are curved. At first sight it seems to be possible to
separate them into two categories, one in which the shaft is about 0.159
mm. long, and another in which it is only 0.05 mm. or even less; and
groups of birotulates of approximately the same length often occur in
the interstices of the skeleton. Spicules of all intermediate lengths
can, however, be found. The average diameter of the shaft is 0.0026 mm.
and of the rotula 0.0106 mm., and the rotula consists of from 6 to 8
spines. The gemmule-spicules vary greatly in size, the longest measuring
about 0.08 × 0.014 and the smallest about 0.034 × 0.007 or even less.
There appears to be in their case an even more distinct separation as
regards size than there is in that of the flesh-spicules; but here again
intermediate forms occur. They are all stout, more or less blunt, and
more or less regularly covered with very short spines; most of them are
distinctly curved, but some are quite straight.
_Gemmules._ The gemmules are firmly adherent to the support of the
sponge, at the base of which they are congregated in groups of four or
more. They vary considerably in size and shape, many of them being
asymmetrical and some elongate and sausage-shaped. The latter consist of
single gemmules and not of a pair in one case. Extreme forms measure
0.38 × 0.29 and 0.55 × 0.25. Each gemmule is covered with a thick
chitinous membrane in close contact with its wall and surrounding it
completely. This membrane is full of spicules arranged as in a mosaic;
most or all of them belong to the smaller type, and as a rule they are
fairly uniform in size. Separated from this layer by a considerable
interval is another layer of spicules embedded in a chitinous membrane
which is in continuity with the basal membrane of the sponge. The
spicules in this membrane mostly belong to the larger type and are very
variable in size; mingled with them are often a certain number of
birotulate flesh-spicules. The membrane is in close contact with a dense
cage of skeleton-spicules arranged parallel to it and bound together by
chitinous substance. The walls of this cage, when they are in contact
with those of the cages of other gemmules, are coterminous with them.
There is a single depressed aperture in the gemmules, as a rule situated
on one of the longer sides.
This sponge is distinguished from _C. burmanica_ not only by differences
in external form, in the proportions of the spicules and the structure
of the skeleton, but also by the peculiar nature of the armature of the
gemmule. The fact that birotulate spicules are often found in close
association with them, is particularly noteworthy.
TYPE in the Indian Museum.
GEOGRAPHICAL DISTRIBUTION.--This sponge has only been found in the
Western Ghats of the Bombay Presidency. _Localities_:--Igatpuri Lake and
the R. Godaveri at Nasik.
BIOLOGY.--There is a remarkable difference in external form between the
specimens taken in Igatpuri and those from Nasik, and this difference is
apparently due directly to environment. In the lake, the waters of which
are free from mud, the sponges were growing on the lower surface of
stones near the edge. They formed small crusts not more than about 5 cm.
(2 inches) in diameter and of a pale greyish colour. Their surface was
flat or undulated gently, except round the oscula where it was raised
into sharply conical eminences with furrowed sides. The specimens from
Nasik, which is about 30 miles from Igatpuri, were attached, together
with specimens of _Spongilla cinerea_ and _S. indica_, to the sides of a
stone conduit full of very muddy running water. They were black in
colour, formed broad sheets and were markedly corrugated on the surface.
Their oscula were not raised on conical eminences and were altogether
most inconspicuous. The skeleton was also harder than that of sponges
from the lake.
In the lake _C. lapidosa_ was accompanied by the gemmules of _Spongilla
bombayensis_, but it is interesting that whereas the latter sponge was
entirely in a resting condition, the former was in full vegetative
vigour, a fact which proves, if proof were necessary, that the similar
conditions of environment do not invariably have the same effect on
different species of Spongillidæ.
APPENDIX TO PART I.
FORM OF UNCERTAIN POSITION.
(Plate I, fig. 4.)
On more than one occasion I have found in my aquarium in Calcutta small
sponges of a peculiar type which I am unable to refer with certainty to
any of the species described above. Fig. 4, pl. I, represents one of
these sponges. They are never more than about a quarter of an inch in
diameter and never possess more than one osculum. They are
cushion-shaped, colourless and soft. The skeleton-spicules are smooth,
sharply pointed, moderately slender and relatively large. They are
arranged in definite vertical groups, which project through the dermal
membrane, and in irregular transverse formation. Small spherical
gemmules are present but have only a thin chitinous covering without
spicules or foramen.
These sponges probably represent an abnormal form of some well-known
species, possibly of _Spongilla carteri_. I have seen nothing like them
in natural conditions.