Chapter VIII: Introduction: To Part I (4)

_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.

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.

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.

_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.

_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.

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.

_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.

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.

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).

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.

_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.