174 



THREE CRUISES OF THE " BLAKE.' 



was the first to show that the sponge and siUceoiis cable were 

 one organism, and the polyps mere parasites attached to it above 

 the mud and below the sponge (Fig. 528), a view which has 

 been fully confirmed. Asconema setuhcdense, a magnificent sili- 

 ceous sponge, first dredged by Kent off the coast of Portugal, 

 has a wide geographical distribution. Very fine specimens were 

 collected by the "Talisman," and one of the adjoining figures 





Fig. 531. — Holtenia Pourtalesii. |. 



(Eig. 529) is taken from one of the best preserved specimens 

 of the French expedition. It is a common species in the West 

 Indies, in from 300 to 600 fathoms. Flier onema Annce (Fig. 

 530), first described by Leidy, is represented by some most 



