BRITISH SP0NG1AD.E. 345 



Desmacidon, Bowerbank. 



Section * Skeleton spicula, acerate. 



1. Desmacidon fruticosa, 



2. Jeffreysii, 



Section * * Skeleton spicula, acuate. 



3. Desmacidon Peachii, 



4. constrictus, 



Section * * * Skeleton spicula, spinulate. 



5. Desmacidon cegagropila. 



1. Desmacidon fruticosa, Bowerbank. 



Halichondkia fkuticosa, Johnston. 



Sponge. Sessile, massive, and roughly latticed, or massive, 

 with large projecting cloacal fistulse. Fistular cloacae 

 very large and deep. Oscula simple, numerous ; on 

 the surface in young specimens, or on the parietes of 

 the cloacae, when they are present. Surface hispid. 

 Pores inconspicuous. Dermal membrane pellucid, 

 spiculous ; tension spicula acerate, dispersed, not 

 numerous ; retentive spicula of sarcodous surface bi- 

 hamate, simple, and contort, variable in size, very 

 numerous ; and also bidentate equi-anchorate, large 

 and small, few in number, comparatively. Skeleton. 

 Fibre stout and numerously spiculous ; spicula acerate 

 or occasionally inequi-acerate. Interstitial membranes. 



