BRITISH SPONGIAD^l. 119 



denuded of these spicula, has the appearance, to the 

 unassisted eye, of woody structure, and it is very rigid 

 and brittle. 



I have not seen fresh specimens of this species, but it is 

 highly probable that when alive the surface spicula would 

 not project to anything like the same extent as represented 

 in the dried condition. 



11. Dictyocylindrus rugosus, Bowerbank. 



Sponge. Ramose, pedicelled, branching irregularly, short, 

 thick, and fleshy. Surface rugose, slightly hispid. 

 Oscula simple, large, dispersed, few in number. Pores 

 inconspicuous. Dermal membrane pellucid, aspiculous. 

 Skeleton : axial spicula cylindrical, long, slender, very 

 flexuous ; or sub-fusiformi-inequi-acerate, long and 

 slender; rarely acuate. Radial skeleton, fasciculated; 

 fasciculi compound ; spicula numerous, successive from 

 base to apex, acuate, comparatively short and stout. 

 External defensive spicula, terminal spicula of the 

 radial fasciculi. 



Colour. Alive, light gray, with a tinge of yellow. 

 Habitat. Orkney and Shetland, Captain Thomas, Mr. 

 Barlee, Rev. A. M. Norman, and Mr. C. W. Peach. 

 Examined. In the fresh state. 



This sponge is by no means a rare species in the localities 

 named. It rarely exceeds three inches in height, and the 

 principal stem often exceeds half an inch in thickness. It 

 usually begins to divide near its base, generally dichoto- 

 mously, but sometimes trichotomously. The branches are 

 frequently somewhat compressed, and they preserve the 

 same diameter for nearly their whole length, terminating 

 obtusely. 



In the living or fresh state the central axis occupies 

 about one third of the diameter of the sponge. The radial 

 fasciculi have but few spicula at their bases, but they 



