Mr. H. J. Carter on the Freshwater Sjwnges of Bombay. 83 



of its texture, and the smallncss of its seed-like bodies and 

 spicula. 



2. Sp.friabilisl Lam. — Amorphous, surface irregularly con- 

 vex, presenting low ridges or eminences. Vents situated on the 

 latter, large, crateriform. Colour bright green on the surface, 

 faintly yellow towards the interior. Growing in circumscribed 

 masses on fixed bodies, or enveloping floating objects ; seldom 

 attaining more than 2 inches in thickness. Texture loose, friable. 

 Structure confusedly fibrous, reticulate, sometimes radiated. Seed- 

 like bodies spheroidal, about Xth of an inch in diameter, pre- 

 senting smooth points externally. Spicula of two kinds, large 

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

 ends, about -gjth. of an inch in length ; small spicula also slightly 

 curved, smooth, pointed at each end, about jj^th of an inch in 

 length. (Plate III. fig. 3.) 



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

 rocks, stones or gravel ; or temporarily on floating objects ; sel- 

 dom covered by water more than six months in the year. 



Observations. — The colour of this species is bright green when 

 fresh, but this fades after it becomes dry. It seldom throws up 

 projections much beyond its surface ; does not appear to be in- 

 clined to spread much ; and is matted and confused in its struc- 

 ture towards its base and round its seed-like bodies. From the 

 other sponges it is distinguished by the smooth spicula which 

 surround its seed-like bodies and the matted structure just men- 

 tioned. Its green colour combined with the smoothness of its' 

 spicula, both large and small, is useful in distinguishing it from 

 the other species, but without the latter it is deceptive, because 

 Sp. alba and Sp. plumosa become green under certain circum- 

 stances. It appears to be Sp. friabilis, Lam., from no mention 

 having been made by Dr. Grant (in his description of this spe- 

 cies*) of the presence of any but smooth pointed spicula in it, 

 and the appearance of " transparent points n studding the surface 

 of its seed-like bodies, which is not observable in any of the other 

 species, wherein the small spicula are spiniferous or stelliferous. 



3. Sp. alba, n. s. — Flat or elevated, surface slightly convex, 

 presenting gentle eminences and depressions or irregularly formed 

 projections. Vents large, scattered. Colour yellow, growing 

 horizontally, in circumscribed masses or in irregular patches, 

 encrusting objects, seldom attaining more than an inch in thick- 

 ness. Texture coarse, open. Structure reticulated. Investing 

 membrane abounding in minute spicula. Seed^like bodies sphe- 

 roidal, about ^ n th of an inch in diameter, presenting rough points 

 externally. Spicula of two kinds, large and small ; large spicula 



* Edinb. Phil. Trans, vol. xiv. pp. 274 and 279. 



6* 



