214 THE VOYAGE OF H.M.S. CHALLENGEK. 



the one being found mainly in the dermal crust and scattered through the soft tissues, 

 and the other in the stout fibres. 



This is a very pretty and interesting little species ; it seems to be perfectly distinct 

 from all previously known, and its habit of agglutinating comparatively large foreign 

 objects on to the surface of the body is very peculiar, although other species may acquire 

 an accumulation of minute particles of dirt. One function of this crust is possibly to 

 conceal the sponge from its enemies. 



The skeleton arrangement in the fistular processes calls to mind the corresponding 

 arrangement in Proteleia sollasi, but there is only a single, though more regular circle 

 of fibres {cf. figs. 3 and 7, PI. XLIL). The number of these fibres appears to be 

 inconstant. 



Zoca%.— Station 75, July 2, 1873; lat. 38° 38' 0" N., long. 28° 28' 30" W.; off 

 the Azores ; depth, 450 fathoms ; bottom, volcanic mud. Two specimens. 



Genus Proteleia, Dendy and Ridley (Pis. XLIL XLIV.). 



1886. Proteleia, Dendy and Kidley, Ann. and Mag. Nat. Hist, ser. 5, vol. xviii. p. 152. 



Sponge sessUe, corticate ; ujjper surface covered with mammiform processes. 

 Megasclera tylostylote and (or) stylote ; and also spicules with grapnel-like apices pro- 

 jecting freely beyond the surface of the sponge. 



This is one of the most interesting of the new genera which we have been obliged to 

 found. It comes very close to Polymastia but differs from that genus in the possession 

 of the grapnel-like spicule. This feature seems to approximate it to the Tetractinellida, 

 but this question has been fully discussed by us elsewhere {vide Ann. and Mag. Nat. 

 Hist., loc. cit.). 



Proteleia sollasi, Dendy and Eidley (PL XLIL figs. 6, 7, 8, 8a, 8b, 8c, 8c/, 8e, 8/ 

 8g, 8h ; PL XLIV. fig. 2). 



1886. Proteleia Sollasi, Dendy and Eidley, Ann. and Mag. Nat. Hist., ser. 5, vol. .wiii. p. 153, 

 pi. V. 



Sponge (PL XLIV. fig. 2) sessile, apparently coating, consisting of a fiattened, 

 cake-like expansion with slightly convex upper surface, from which arise abruptly 

 numerous short, thick, cylindrical, mammiform projections of various sizes. The single 

 specimen in the collection is about G3 mm. long by 31 mm. broad, and about 13 mm. 

 thick. The mammiform processes vary somewhat in size, being, when full grown, 

 about 8 mm. long by 4 mm. in diameter at the base; they are almost solid and 

 very stiff and firm, contrasting strongly with those of Polymastia rohusta and Poly- 

 mastia mammillaris in this respect, at present they are all closed at the summit, and 



