BRITISH SPONGIADjE. 105 



S. cristata, is a very young specimen of our D. ramoms, 

 possessing none of the adult characters of that species, but 

 agreeing with it precisely in the mode of arrangement, and 

 in the form and propoition of the spicula of the skeleton, 

 and of the internal defensive ones also. The form of the 

 specimen has evidently misled Montagu, and induced him 

 to believe it was of the same species as Ellis's S. cristata, 

 which is certainly one of the many varieties of HaUchondria 

 panicea found abundantly on the reefs of rocks off Hastings 

 that are submerged excepting at low water. 



3. DiOTTOCTLiNDRUs RADiosus, Bowerhanh. 



Sponge. Pedicelled, branching dichotomously in nearly 

 the same plane, compressed. Surface even, hispid. 

 Oscula simple, dispersed, minute. Pores inconspi- 

 cuous. "Dertnal membrane spiculous, tension spicula 

 acerate, long, and extremely slender, often flexuous, 

 dispersed or loosely fasciculated. External defensive 

 spicula congregated in distinct and separate radiating 

 fasciculi, nearly equidistant r spicula large and fong. 

 Skeleton. Axial spicula acerate and acuate, stout, 

 and very long. Interstitial membrane spiculous ; 

 spicula same as those of the dermal membrane, rather 

 numerous. 



Colour. — Dried, nut-brown. 



Habitat. — ^Vazon Bay, Guernsey, Mr. Cooper. 



Examined. — In the dried state. 



I am indebted to my friend the Rev. A. M. Norman, 

 for my knowledge of this sponge, he received it, with other 

 interesting specimens, from Mr. Cooper, of Guernsey, in 

 1865. It is two and a half inches high, and three inches 

 in width ; it has not its natural base. At seven lines above 

 its present base it divides into two principal branches, and 

 it continues to subdivide dichotomously at unequal dis- 

 tances to near the distal terminations of the branches. 



