26 A MONOGRAPH OF THE 



render the arming of that part of the sponge unneces- 

 sary. 



The spicular ray is much stouter and longer than the 

 rays of the spiculum on which it is based. The external 

 surface of the sponge is strengthened and supported most 

 effectually by numerous very large, stout, fusiformi-acerate 

 spicula, which are all disposed in the direction of its long 

 axis ; they are readily to be seen by the aid of a lens of an 

 inch focus. 



4. Grantia tessellata, Bowerbank. 



Sponge. Elongately oval, sessile ; surface even, tessel- 

 lated, densely hispid. Cloaca central, cylindrical, 

 nearly as long as the sponge ; armed internally with 

 spiculated, equiangular, triradiate spicula ; spicular ray 

 eiisiform, short, stout, and curved. Mouth of cloaca 

 armed with a thick ciliary fringe of long, rigid, 

 acerate spicula. Base of the ciliary fringe strength- 

 ened with numerous rectangulated triradiate spicula, 

 with the coincident radii disposed at right angles to 

 the ciliary spicula, and the third ray directed towards 

 their bases. Oscula simple, slightly depressed, as 

 numerous as the interstitial cells. Pores inconspi- 

 cuous. Interstitial cells : distal terminations obtuse ; 

 furnished each one with a dense corymboid fasciculus 

 of short acerate spicula. Skeleton spicula equi- 

 angulated and rectangulated triradiate ; radii attenu- 

 ating, stout. 



Colour. — ^Brown. 



Habitat. — Guliot caves, Sark, Mrs. Buckland; off 

 Fermaiu Bay, Guernsey, 13 fathoms. Rev. A. M. Norman. 

 Examined. — In the dried state. 



I am indebted to my kind friend the late Mrs. Buck- 

 land, an able and enthusiastic zoologist, for this new and 

 interesting species of Grantia. 



