BRITISH SPONGIADjE. 37 



Colour. White. 



Habitat. Scarborough, Mr. Bean ; Guernsey and Sark, 

 Mrs. Buckland, and J. S. Bowerbank. 

 Examined. In the dried state. 



The specimens of this sponge, which I have received 

 from my friend Mr. Bean, of Scarborough, are thin, with 

 sinuous crests running over the surface, on the highest part 

 of which are the mouths of the cloacae. Those from my 

 late friend Mrs. Buckland, and also those I have found, 

 were from the Guliot Caves, Sark, and other localities in 

 the Channel Islands ; these specimens are more massive, 

 and the surface is furnished with from one to seven or 

 eight conical lobes, each terminated by the mouth of a 

 cloaca. The cloacae are separate and distinct organs, at 

 the base of each there is usually the terminations of one or 

 more large excurrent canals ; and on all parts of the walls 

 of the cloaca there are numerous dispersed oscula. The 

 defensive spicula of the parieties of the cloacae are remark- 

 able, and disproportionately large. The equiangular tri- 

 radiate bases are buried deep in the interstitial tissues, 

 while the spicular rays passing through the walls of the 

 cloaca project for about half or two thirds their length into 

 its cavity, presenting a formidable array of weapons to 

 greet any intruder, while the basal radii perform an im- 

 portant part in strengthening the skeleton. The basal 

 radii of some are nearly approaching to the rectangular 

 form, but the normal form is equiangular. 



The unicurvo-cruciform spicula abound on the membranes 

 lining the cloacae of the sponge. Their axial radii are dis- 

 posed very nearly in the direction of the long axis of those 

 organs, and the curves formed by the lunate radii always 

 have their points towards the mouth of the cloaca. They 

 are always lying on one of their flat sides, and when undis- 

 turbed I have never seen any one of the radii projected 

 out of the plane of the membrane on which they are re- 

 posing. The apical ray often projects for the whole of its 

 length over the margin of the terminal orifices of the inter- 

 stitial excurrent canals, so as to appear to perform the 



