FLATE LXXXIX. 313 



compact, but rather slender ; spicula acuate, rather 

 short and stout. Interstitial membranes aspiculous or 

 very sparingly spiculous ; spicula same as those of the 

 skeleton. 



Colour. In spirit, light ochreous yellow. 



Habitat. Jersey ; Rev. A. M. Norman. 



Examined. From spirit. 



This sponge in a bottle of spirit was sent to me by 

 my friend the Rev. A. M. Norman, who dredged it at 

 Jersey in 1867. It is based on the side of a small 

 fucoid stem about one tenth of an inch in diameter. 

 It is an inch in height, three fourths of an inch broad, 

 and about half an inch in thickness. Its surface is 

 open and very uneven and ragged in appearance ; but 

 from the state of the interstitial membranes and the 

 sarcode with which they are coated, it was evidently in 

 a living state when taken. There is a remarkable 

 paucity of structural characters. Excepting a few, 

 evidently extraneous spicula, there was one form only 

 in the structures, and that was acuate, rather short, 

 and very variable in diameter. On some parts of the 

 dermal membrane there were a few of these spicula 

 irregularly disposed, while other parts were aspiculous 

 and the same observation applies equally well to the 

 interstitial membranes. 



Notwithstanding a very careful examination of the 

 membranes in sitii and of the spicula prepared by 

 nitric acid, I could not find the slightest trace of any 

 one of the forms of retentive spicula that are usually 

 found in the structures of the Desmacidons. Our de- 

 pendence for the recognition of the species rests only on 

 its external characters and the form of its skeleton 

 spicula, and it is fortunate that both these characters 

 are very effective in its discrimination, and the spicula 

 especially so ; they are distinctly different in size and 

 proportions to those of any other known species of 

 British Desmacidon. The negative evidence of the 

 total absence of the retentive spicula is also valuable in 

 determining the species. 



