1863.J DR, /. S. BOWERBANK ON THE SPONGILLIDiE. 465 



central portion of the shaft, towards which part they are also fewer 

 in number and less both in height and curvature : unlike those of 

 the dermal membrane, the spines on these spicula are always acutely 

 terminated. 



To obtain a satisfactory definition of the spines of both these spi- 

 cula, a power of about 600 linear should be used. The acerate spi- 

 cula of the skeleton are about three times the length of those of the 

 ovaria, and are also three or four times their diameter. 



Spongilla cerebellata, Bowerbank. 



Sponge massive, sessile ; surface furnished abundantly with short 

 compressed branches, finely hispid. Oscula large, numerous, dis- 

 persed. Pores inconspicuous. Dermal membrane thin, translucent, 

 spiculous ; spicula slightly curved, cyhndrical, entirely spined ; spines 

 of the middle of the shaft cyhndrical ; terminations obtuse, expanded 

 or branched ; spines towards the ends of the shaft conical, acute, 

 recurved. Ovaria globose, smooth ; spicula disposed more or less 

 at right angles to lines radiating from the centre of the ovarium, of 

 the same form as those of the dermal membrane. 

 • Colour, dried state, light grey. 



Hab. Freshwater tanks near Aurungabad, dominions of the Ni- 

 zam, East Indies {Dr. Bradley). 



Examined in the dried state. 



I received this Spongilla from my friend Mr. Henry Deane, of 

 Clapham, who informed me that it was sent to him from the East 

 Indies by Dr. Bradley, who was in the service of the Nizam, and who 

 had it sent to him from some water-tanks about 100 miles from Au- 

 rungabad, in the Nizam's dominions. Its dimensions are 6 inches 

 in length, 4 inches in width, and 2t inches in height. The general 

 surface is very irregular and cavernous, and has much resemblance 

 to the surface of the brain of an animal ; towards one end these irre- 

 gularities are developed into short compressed branches, the surfaces 

 of which are even and minutely hispid. The general texture of the 

 Sponge is exceedingly friable, and the short branches afford nearly 

 the only parts of the surface which has the dermal membrane re- 

 maining upon it. The dermal membrane is very thin and translu- 

 cent, and is furnished with slightly curved, cyhndrical, entirely spined 

 spicula, the spines of which at the middle of the shaft are stout and 

 cylindrical, with obtuse or expanded and sometimes slightly branched 

 terminations, while those towards the ends of the shaft are acutely 

 conical and are curved backwards towards the middle of the shaft. 

 The ovaria are imbedded in every part of the Sponge in remarkable 

 profusion ; when expanded by immersion in water, they are perfectly 

 globular, and have a smooth surface ; when viewed by the aid of a 

 Leiberkuhn and a power 100 linear, the spicula are so far imbedded 

 as to be scarcely visible. They are of the same size and form as 

 those of the dermal membrane. The imbedment of the spicula in 

 the wall of the ovary is rarely parallel to the outer surface, nor are 

 they confined to that part of the wall as in some closely alhed species, 

 but are dispersed throughout the whole of its substance, at various 



Proc. Zool, Soc— 1863, No. XXX. 



