PLATE LXXXII. 269 



The interior space is very rugged and uneven, with 

 numerous irregular conical projections. 



There are a few simple oscula on the exterior of the 

 sponge, but they appear to be very much more numerous 

 on the inner surface, which seems to exercise the 

 function of a large irregular cloaca, receiving the oscular 

 excurrent streams and discharging its ftecal contents 

 through the great openings on the surface. 



On the greater portion of the dermal membrane the 

 tension spicula form a distinct but irregular reticulation, 

 which is visible in the dried specimen by the aid of a 

 lens of about two inches focus ; but in other parts the 

 tension spicula are irregularly and thickly dispersed on 

 its surface; their form is more purely acuate than those 

 of the skeleton. There is little danger of confounding 

 this species with either D. constrictus or D. PeacJiii, the 

 comparative size of its skeleton spicula alone sufficing 

 to distinguish it, as they are only about half the size of 

 those of the former species and not more than about 

 one third the length of those of the latter one ; and the 

 comparatively short, stout, retentive spicula of D. caver- 

 mda are in strong contrast with the large but delicately 

 slender ones of D. Peachii. 



EciONEMiA COACTUEA, Bowerhwiik. 



Plate LXXXII. 



Sponge massive, unattached, collecting on its surface 

 numerous small pebbles and other extraneous matters. 

 Surface even, minutely granulated, and occasionally 

 hispid. Oscula and pores inconspicuous. Dermis. 

 Primary external defensive spicula subfusiformi-acerate, 

 lono- and stout ; secondary external defensive spicula 

 fusiformi-acerate, long and very slender ; terminations 

 exceedingly attenuated, few in number. Dermal mem- 

 brane thin and pellucid; pores numerous and large, 

 congregated in the areas between the groups of termi- 

 nal heads of the connecting spicula. Dermal membrane 



