464 DR. J. S. BOWERBANK ON THE SPONGILLIDiE. [NoV. 24, 



with the same spicula as those of the dermal membrane. Skeleton- 

 spicula fusiformi-acerate, large, and stout. Ovary-spicula disposed 

 at right angles to lines radiating from its centre, cylindrical, stout, 

 curved, entirely spined ; spines acute, those at the ends of the spi- 

 cula recurved. 



Colour, alive, yellow, occasionally green {Carter). 



Hah. Tanks, Bombay (Carter), 



Examined in the dried state. 



Mr. Carter, in his excellent paper on the " Freshwater Sponges in 

 the Island of Bombay," describes this species as having a "flat or 

 elevated surface, slightly convex, presenting gentle eminences or de- 

 pressions or irregularly formed projections." The whole of these 

 characters of form, there is no doubt, are correct as regards particular 

 specimens. The mass for which I am indebted to Mr. Carter is a 

 complete specimen about 3 inches in diameter, and exceeding 2 inches 

 in height, having several short, stout, ramifying branches thrown out 

 from its surface precisely as described by him, in the observations 

 following his specific descriptions, as occurring when the species is 

 found in circumscribed portions. 



The oscula are large, and, in the specimen under consideration, 

 they are not scattered, but are congregated in distinct groups in, 

 consequence of the convergence of the excurrent canals on particular 

 parts of the surface of the Sponge ; in tlie specimen ixnder consider- 

 ation there are four such groups, in which the oscula are all more or 

 less confluent, forming in three out of the four cases a common ori- 

 fice exceeding half an inch in diameter. This character is exceed- 

 ingly striking, and does not appear to occur in any other species 

 described as being found at Bombay. 



The disposition of the spicula in the dermal membrane is very 

 variable : sometimes they form a well-defined uniserial or biserial net- 

 work ; while at others they are dispersed in great profusion and with- 

 out any approach to arrangement. They are long and slender in 

 their proportions, and vary considerably in the amount of curvature 

 they assume ; and the obtuse spines with which the whole of the shaft 

 is furnished are most abundant. They are small towards the apices 

 of the spiculum, and increase in size as they approach the centre of 

 the shaft, where they often attain an altitude equal to the largest 

 diameter of the spiculum on which they are based, and they are 

 nearly of the same diameter from base to apex. The same descrip- 

 tion of spicula are abundantly dispersed in the interstitial mem- 

 branes, but do not appear to approach in any degree a reticulated 

 arrangement. 



The spicula of the ovaria are imbedded irregularly in the surface 

 of its coriaceous coat ; they slightly exceed in length those of the 

 dermal and interstitial membranes, but they are two or three times 

 their greatest diameter. They vary considerably in the degree of 

 their curvature, and attenuate slightly from the centre of the shaft 

 towards each end of the spiculum. The spines with which they are 

 furnished are most abundant at their terminations, where they are 

 thickly clustered, and are very much curved in the directioa of the 



