320 THE VOYAGE OF H.M.S. CHALLENGER. 



slender diverging branches, each provided with a pear-shaped barbed terminal swelling. 

 The branch stalks are smooth or rough, and either straight or uniformly curved towards 

 the exterior, or occasionally slightly flexuous (PI. LXXXVI. figs. 5, 9). This seems to 

 vary according to habitat, but also according to the individual. 



The gastral skeleton consists exclusively of long rod-like diacts, which are rough 

 throughout or terminally, and are provided with a central node of intersection. Their 

 extremities, which are embedded in the gastral membrane, are simply rounded or slightly 

 swollen. Of gastral hexacts or scopulse I have found no trace. 



The uncinates of the parenchyma vary greatly in length and form. Sometimes the 

 greatest breadth occurs just about the middle, sometimes nearer the outer extremity ; 

 sometimes the barbs are densely crowded, sometimes more widely disposed, and so on. 



The numerous irregularly scattered hexasters are, on the one hand, oxyhexasters with 

 a variable number of terminal rays, which are not unfrequeutly curved, similar in fact to 

 forms already described in the other species of Aphrocallistes (PI. LXXXVI. figs. 6, 11), 

 and, on the other hand, regular or irregular discohexasters in which the terminal rays 

 are also curved, and provided with rounded terminal knobs (PL LXXXVI. fig. 10). In 

 addition to these, simple regular hexacts occur, in some specimens very abundantly. In 

 these the rays are slender and tolerably long, smooth or rough, and always ending in 

 fine points (PI. LXXXVI. fig. 7). 



The soft parts, which I was able to examine on some well-preserved spirit specimens, 

 do not differ in disposition or minute structure from what has been already described in 

 Aphrocallistes hocagei. 



Family IIL Coscinoporid^, Zittel (Pis. LXXXVII.-XCL). 



The plate-like wall of the cup-, goblet-, or plate-shaped, firmly attached body is trans- 

 versely penetrated by more or less elongated funnel-shaped straight canals, which open 

 alternately on one or other surface (covered only by the sieve-like bounding skin), but are 

 pointed and blend at the other end. Their length thus always corresponds to the thick- 

 ness of the sponge body-wall. 



Genus Chonelasma, n. gen. (Pis. LXXXVII.-XCL). 



The dictyonal framework of the beaker or almost plate-hke specimens is traversed 

 by two systems of oppositely directed funnel-shaped meshes or passages, which appear so ' 

 arranged that each blind funnel extremity of the one system always occurs between the 

 circumjacent funnel openings of the adjoining passages of the other and oppositely 

 directed system. Those oppositely directed passages represent the incurrent and ex- 



