BRITISH SPONGIAD^E. 41 



ciliary defensive sponge, are very short and few in number. 

 The pores in Professor Forbes's sponge are barely visible 

 with the aid of a two inch lens. The oscula are very nu- 

 merous and minute, but they are visible to the unassisted 

 eye in dried specimens. 



From the difference in the form and size of the speci- 

 mens under consideration, it would appear that this species 

 is subject to much variation in both of these characters. 



Since the above was written, my friend the Rev. A. M. 

 Norman has taken fourteen specimens of this sponge off 

 Saint's Bay, Guernsey, in 1865, several of them rather 

 exceeded two inches in length, and three of them did not 

 exceed seven lines in length, with a proportionate decrease 

 of diameter, the others were intermediate between the two 

 extremes ; in every other respect they agreed perfectly with 

 the two specimens previously described. 



3. Leuconia pumila, Bowerbank. 



Sponge. Sessile, elongo-oval, surface smooth ; oscula 

 simple, on the parieties of the central elongated 

 cylindrical cloaca, Internal defensive spicula, spicu- 

 lated, equi-angular, or rectangular triradiate spicula ; 

 spicula r ray short, attenuated. Cloaca cylindrical, 

 extending from the base to the distal end of the 

 sponge, mouth simple, membranous, thin. Pores in- 

 conspicuous. Sketeton spicula equi-angular, trira- 

 diate, very large and strong, variable in their propor- 

 tions. Interstitial membranes. Spicula equi-angular, 

 triradiate, small and slender. 



Colour. Cream white, alive and dried. 

 Habitat. Guernsey, Rev. A. M. Norman. 

 Examined. In the dried state. 



Pour specimens of this sponge were obtained by the 

 Rev. A. M. Norman while dredging in company with 

 Mr. Jeffreys, off Guernsey. The largest does not exceed 



