BRITISH SPONGIADiE, 167 



Norman ; Salcombe Bay, Devon, and Menai Straits, Mr. 

 Joshua Alder ; Weymouth Bay, Mr. William Thompson, 

 Eosamined.. — In the living state. 



This species is one of the best tjrpes of the structural 

 peculiarities of the genus to which it belongs. It is abun- 

 dant on the rocks between high and low Avater mark in St. 

 Katherine's Cave, at Tenby, and on other parts of the neigh- 

 bouring rocks. It occurs in iiTegular patches, sometimes 

 five or six inches in diameter, and from half to one inch in 

 thickness, varying in colour from a light yellow orange to a 

 deep red orange, and sometimes having a slight tint of 

 green. In its live condition it is firm and flesh-like, both 

 to the sight and the touch, and this appearance attends it 

 also in the dried state. The oscula are few in number, and 

 rarely exceed a line in diameter. The pores are barely 

 visible in a dried specimen through a two-inch lens. The 

 dermal membrane is abundantly supplied with spicula, 

 similar in form to those of the skeleton, but much more 

 slender ; they are closely, but regularly, matted together. 

 The tension spicula are not numerous ; they are of the same 

 form as those of the skeleton, but slender and often flexuous, 

 and some of them are of extreme tenuity. 



I never detected gemmules in either the Tenby or the 

 Sark specimens ; but in one from Bantry Bay, three and a 

 half inches in length by about one and a half broad, and 

 half an inch in thickness, sent to me for examination by the 

 Rev. Mr. Norman, I found them scattered rather sparingly 

 through the tissues. They were spherical, membranous, 

 and aspiculous, and filled with minute vesicles. The largest 

 I observed measured j^th of an inch in diameter, and a 

 smaller one ^i\i of an inch. The colour was that of dark 

 red amber. The specimen sent to me by Mr. William 

 Thompson, of Weymouth, was five inches in length, three 

 inches in width, and about three fourths of an inch in 

 thickness, having the surface covered with small rugged 

 mammseform projections. In April, 1854, I found several 

 specimens of this sponge on the base of the rocks at low- 

 water mark spring tides opposite the archwav dividing St. 



