the ^ Challenger ^ Monaxonida. 489 



of the sponge, with globuhir heads, size '3 by '016 millim. 

 Spicules of cortex spinulate or subspinulate, iaterinadiate in 

 size. 



Localities. Station 73, off tlie Azores, 1000 fath. ; Station 

 184, S.E. off Cape York, Australia, 1400 fath. 



Tricliostemma irregularis^ n. sp. 



Resembling T. Sarsii in general shape, but less regular, 

 thicker, and with strongly hispid upper surface. Diameter 

 •| inch, thickness ^ inch. Skeleton arranged as in T. Sarsii. 

 Spicules, all spinulate or subspinulate, of very variable length, 

 those of cortex and interior much longer and slenderer 

 than in T. tiarsii, tlie former often projecting 1 millim beyond 

 the surface 5 size of the latter about '5 by '012 millim., often 

 longer. 



Locality. Station 299, west of Valparaiso, 2160 fath. 



Genus Tentorium * (Vosmaer). 



Sessile, columnar or conical, with a dense cylindrical 

 sheath of large, external, longitudinally arranged spicules. 

 On the top a proper cortex containing ■ bundles of smaller 

 spicules with large subdermal cavities between them. Pores on 

 upper surface only. Oscula tubular, in centre of upper surface. 



\Tentorium semisuberites (Schmidt). 



Localities. Stations 49 and 50 : S. of Nova Scotia, 85 and 

 1250 fath. ; Inaccessible Island, South Atlantic, 60-90 fath.] 



Genus Stylocoedyla (Wyville Thomson). 



Corticate. With distinct head and stalk. Skeleton in 

 head radiate, with cortical layer of smaller spicules, Skeleton- 

 spicules acerate. 



\Stylocordyla stipitata (Carter). 



Localities. Station 49, South of Nova Scotia, 85 fi.th. ; 

 Station 147, Southern Ocean, 1600 fath.; off Bahia 7-20 

 fath. (Station 145, Southern Ocean, and off Kerguelen, 

 10-100 fath. : var. globosuj u. j characterized by globular bullet- 

 like head.) ] 



Genus QuASiLLiNA (Norman). 



Sponge corticate, stipitate, with oval body f, bearing a single 



* = Thecopliora, Schmidt. 



t The soft internal tissues generally shrink up and disappear, and 

 thus give to the sponge a characteristically hollow form. 



