BRITISH SPONGIADjE. 235 



Interstitial membranes thin and translucent ; spicula 

 same as those of dermal membrane, but less in 

 number. 



Colour. Dried, light gray. 



Habitat. Tenby, Mrs. Brett. Guernsey, Rev. A. M. 

 Norman. Scarborough, Mr. Bean. 

 Eocami7ied. In the dried state. 



The structure of this sponge is very irregular. It is 

 composed of loosely aggregated fascicula of spicula which 

 form a very irregular and disconnected network, and the 

 spicula of the bundles appear to have been but very slightly 

 cemented together with keratose structure; other spicula of 

 the same form and size are irregularly disposed amid the 

 network. The interstitial membranes are very thin and 

 pellucid, and when mounted in Canada balsam are scarcely 

 visible. The dermal membrane in adult specimens is 

 crowded with spicula of the same size and form as those of 

 the skeleton, with, occasionally, others of the same form, 

 but small and slender. In the specimen found by Mrs. 

 Brett at Tenby, there were more of the slender spicula 

 than in the larger and probably older specimens obtained 

 by Mr. Norman, at Guernsey, in which they were rather 

 rare. 



The type specimen in its present form is eight lines in 

 length by six in breadth, and the same in height, but it is 

 evidently a portion only of the original mass. Mrs. Brett, 

 to whom I am indebted for my first acquaintance with this 

 species, found it between high- and low-water marks on the 

 northern side of St. Katherine's Rock, at Tenby. The 

 colour when alive, I am informed, was the same as when 

 dried, light gray approaching closely to white. 



I have subsequently examined a second specimen col- 

 lected by my late friend Mr. Ingpen, and now in the pos- 

 session of the Rev. Alfred M. Norman. It agrees with the 

 type specimen in every respect excepting in its form, which 

 is irregular. Massive towards the middle portion with 

 three short projecting portions, and is evidently modified in 



