Mr. H. J. Carter on the Freshwater Sponges of Bombay. 85 



of its structure, its radiated appearance interiorly, the form of its 

 small spicula, and the manner in which its seed-like bodies are 

 studded with little toothed disks ; and from the following species 

 by the fineness of its texture and the spheroidal form of its seed- 

 like bodies. Probably it is the species alluded to by Dr. John- 

 ston* which was examined by Meyen from the kind and arrange- 

 ment of the small spicula round the seed-like bodies, which how- 

 ever in this species are not cemented together by carbonate of 

 lime as stated by Meyen, but by an amorphous siliceous deposit. 



1 have named it after Meyen, who has characterized it by the 

 description of its minute spicula. 



5. Sp. plumosa, n. s. — Massive, surface convex, presenting 

 gentle eminences and depressions, or low wavy ridges. Colour 

 yellow. Growing in circumscribed masses, attaining a height of 



2 inches. Texture loose, coarse, resistent. Structure coarsely 

 fibrous, reticulated, radiated, fibres fasciculated, spreading from 

 the base towards the circumference in a plumose form. Seed- 

 like bodies ovoid, about gV 1 ^ °f an mcn m tne i r longest dia- 

 meter, studded with little toothed disks. Spicula of two kinds, 

 large and small ; large spicula slightly curved, smooth, pointed 

 at each end, about y-^th of an inch in length ; small spicula 

 straight, sparsely spiniferous, terminated at each end by a toothed 

 disk, about 2~g2 n d °f an i ncn ^ n l en gth. (Plate III. fig. 2.) 



Hab. Sides of freshwater tanks in the island of Bombay, fixed 

 or floating, seldom covered by water more than six months in the 

 year. 



Observations. — This is the coarsest and most resistent 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 

 exceeded 2 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 floating, 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 tem- 

 porary 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 putrescence, during which gas is generated in them, and ac- 

 cumulates in globules in their structure, through which it must 



* Johnston's British Sponges, p. 154. 



