E. OKINOSEANA. — GEN. CHARACTERS. 227 



specimen is sufficiently rigid to keep its shape wheu taken out 

 of the spirit in which it is preserved. 



To illustrate the appearance of the parietes on the inner 

 side, may serve PI. YII, fig. 2. It is taken from a specimen 

 wanting the upper end but otherwise well preserved and which 

 has been longitudinally bisected for this special purpose. The 

 two kinds of openings visible on this side present much the same 

 appearance as in Euplcdella. The openings of the excurrent 

 canals usually measure less than V/-. ram., but occasionally 2 mm. 

 across. Unlike in Etvplectella, the narrow ridges produced by 

 the main skeletal beams are all more or less obliquely disposed 

 and intersect one another at various angles. However, it can be 

 distinctly observed in this as well as in other specimens that 

 certain beams or spicular bundles, lying innermost in the wall 

 and evidently corresponding to the circular beams of iw^j/ec^e//a, 

 are relatively more transversely disposed than others situated 

 nearer the exterior. 



As could be observed in the complete specimen before de- 

 scribed, the skeletal beams of the parietal wall, at the upper end, 

 pass directly into those of the sieve-plate. If, therefore, the cuflt' 

 and all other loose parts be made to fall off the megascleric 

 beams, the framewoik of the lateral wall should be seen to con- 

 tinue itself without any demarcation into the sieve-plate, much 

 in the same manner, I should think, as in that old specimen 

 well-known as the type of Corhitella speciosa (Q. & G.). 



The lower end of the sponge-body shows the larger paren- 

 chymal spicules and their bundles firmly aukylosed by synapticular 

 fusion, which may extend above for about one half or more of 



