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



loplion ahnormalis, Eidley and Deudy (PI. XVII. figs. 5, 7). 



1886. lophon ahnormalis, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviiL p. 350. 



Sponge represented in the collection by two small, cylindrical fragments, the 

 larger of which is branched, and measures 19 mm. in length by 4 mm. in average 

 diameter. Colour in spirit black. Texture brittle and crumbling. Dermal membrane 

 distinct, transparent, perforated by very distinct, round or oval pores. 



Skeleton. — (a) Dermal; a network of tylota, loosely placed. (6) Main; a loose 

 reticulation of stylote spicules. 



Spicules. — (a) Megasclera ; (l) styli (PI. XVII. fig. 5, c), generally spined at the 

 base and also slightly at the apex; size about 0"35 byO'0126 mm. (2) Tylota (PI. XVII. 

 fig. 5, a, b), each with a nearly straight or slightly curved shaft, bearing a distinct spined 

 knob at each end; size about 0"28 by "008 mm. (b) Microsclera ; only the anisochelse 

 appear to be present, but these are of two very distinct sizes. (1) Large palmate aniso- 

 chela3 of the usual lophon type, 0"0378 mm. long, arranged mainly in very fine rosettes 

 (PI. XVII. fig. 7). (2) Smaller anisochelse of about half the size. It is of course 

 possible that the smaller anisochelse are merely young forms of the larger ones, but it is 

 noteworthy that it is the larger ones, and not the smaller, which are arranged in rosettes. 



It is very abnormal to find an Iop)hon without bipocillate spicules (hence the 

 specific name), and in only one other specimen of lophon have we seen the aniso- 

 chelate spicules arranged in rosettes, viz., in a small specimen from Station 142, which 

 we have referred (though the identification must be considered doubtful) to lophon 

 chelifer, considering it as a young form ; in this also the bipocillate spicules were very rare. 



Locality. — Ofi" Marion Island, 50 to 75 fathoms. Two fragments. 



lophon (f) omnivorus, n. sp. (PL XVII. fig. 10). 



Sponge massive, amorphous. Size of specimen 21 mm. long by 8 mm. broad. 

 Colour in spirit light brown. Texture soft, brittle, very fragile (owing to its sandy 

 skeleton). Surface smootL Dermal membrane very distinct, transparent, perforated by 

 numerous round or oval jjores, about 0"035 mm. in diameter, aggregated in groups over 

 subdermal cavities (PL XVII. fig. 10). Oscula doubtful (? on small, prominent papillae). 



Skeleton. — Composed chiefly of foreign bodies arranged so as to form a dermal layer 

 (PI. XVII. fig. 10) and a deeper skeleton, in the same way as the skeleton of other species 

 of the genus lophon. The nature of these foreign bodies is very various, sand grains, 

 Foraminifera, Polyzoa, calcareous sponge sj)icules, foreign siliceous spicules, &c., occur 

 in great profusion, and appear to take the place of the proper megasclera. We have, 

 however, in the dermal membrane a good many tylota, some of which may be proper to 

 the sponge ; the heads and shafts of these are quite smooth and they vary much in 

 size, probably many of them are foreign. 



