BRITISH SPONGIAD^E. 43 



attenuated radii. Skeleton, interstitial cavities rather 

 large, irregular in form. Excurrent canals large, rather 

 numerous, congregated near the middle of the sponge ; 

 their parieties abundantly armed with stout, spiculated, 

 equiangulated triradiate defensive spicula ; spicular 

 ray large and stout ; and also with slender rectangu- 

 lated triradiate and spiculated rectangulated triradiate 

 spicula ; rectangulating rays short and slender. Spi- 

 cula of the skeleton equiangulated, attenuated, trira- 

 diate, large and stout ; and a few very large and stout 

 fusiformi-acerate spicula. Interstitial membranes 

 pellucid, aspiculous. 



Colour. Cream white. 



Habitat. Torquay, Mr. Gosse ; Guliot Caves, Sark, 

 J. S. Bowerbank. 



Examined. In the dried state. 



I am indebted to my friend Mr. Gosse for having called 

 my attention to the differences in external characters of 

 this species and similar sized specimens of Leuconia nivea. 

 A slight microscopical examination of the specimens he 

 sent me, sufficed to convince me that they were not only 

 different as species, but that they were also members of a 

 different genus, being the only British representative of 

 the genus Leucogypsia ; and on examining a considerable 

 number of specimens of Leucojiia nivea that I had collected 

 from the Guliot Caves in Sark, I found among them four 

 fine specimens of Mr. Gosse's sponge which I had over- 

 looked amidst the abundant spoil of those prolific caves. 



The form of Leucogypsia Gossei is massive, with a ten- 

 dency to elongate upward in the larger specimens, which 

 sometimes attain the height of an inch and a half, and at 

 the distal extremity the oscula are usually found, some- 

 times as simple orifices, and at others as slightly elevated 

 simple tubes, about half the height of their own diameter. 

 The colour and variable form and size of these sponges 

 renders them very liable to be confounded with Leuconia 

 nivea by a hasty observer. The spicula of the dermal 



