212 A MONOGRAPH OF THE 



dantly dispersed over the whole length of the spiculum, but 

 are very short and fine. These spicula are very numerous, 

 and they are projected in every direction into the interstitial 

 cavities of the sponge. 1 am indebted for my knowledge 

 of this species to the Rev. A. M. Norman, of Newbottle, 

 Co. Durham. 



35. Hymeniacidon celata, Bowerbank. 



Cliona celata, Grant. 



A. Hancock. Annals and Mag. Nat. Hist., N. S., 



vol. iii, p. 332. 



Gorgonides, A. Hancock. Ibid., p. 333. 



gracilis, A. Hancock. Ibid., p. 334. 



Howsei, A. Hancock. Ibid., p. 336. 



Northumbrica, J. Hancock. Ibid., p. 336. 



Alderi, A. Hancock. Ibid., p. 337. 



corallinoides, A. Hancock. Ibid., p. 337. 



lobata, A. Hancock. Ibid., p. 341. 



vastifica, A. Hancock. Ibid., p. 342. 

 Halichondria celata, Johnston. 



Sponge. Inhabiting perforations and hollow spaces in 

 oyster and other shells, and limestone rocks and 

 boulders. Surface smooth. Oscula simple, or slightly 

 elevated. Pores inconspicuous. Dermal membrane 

 pellucid, abundantly spiculous ; spicula same as those 

 of the skeleton. Skeleton : spicula sub-fusiformi- 

 enormi-spinulate, variable in length and mode of spi- 

 nulation. Sarcode abundant, yellow to dark-amber 

 colour. 



Colour. Alive, yellow, or amber colour. 



Habitat. All parts of the coast of Great Britain in 

 oyster and other shells, and in the limestone rocks of Tenby 

 in abundance. 



Examined. In the living state. 



This sponge is one of the simplest in its anatomical 

 structure of all the British species. In the dried condition 



