MUSEUM OF COMPARATIVE ZOOLOGY. 199 



form with G. elegans, but dififers wholly in the pattern of its color marks 

 from both G. elegans and G. panamense. G. zebra Richters, from Mauritius, 

 is witliout mucli doubt the same as G. fasciolalum. Ortmaiin has lately re- 

 corded a Gnathophyllum from Tahiti as a new species, G. pallidum. It differs 

 from G. fasciolatum only in the absence of color marks, — a difference due 

 possibly to the action of alcohol. 



Family CRANGONID-SI. 



Sclerocrangon atrox, sp. nov. 



Of the described species of Sclerocrangon, S. ferox G. O. Sars comes nearest 

 to this species. These are some of the chief points of difference. In S. ferox 

 the upturned rostrum is simple, while in S. atrox a long acute tooth is given 

 off from its ventral side, a tooth which reaches as far forward as the tip of the 

 rostrum. In the former species the dorsal carinse of the sixth abdominal seg- 

 ment bear two pairs of well developed spines, while in the latter species one 

 finds but one pair of very small spines at the posterior end of the carinae. The 

 pleural spines of the abdomen are much longer in the former than in the lat- 

 ter, and on the fifth somite there are four to five spines on each pleura against 

 two in S. atrox. The eyes are much smaller in S. ferox, and lack the spine 

 above the cornea seen in S. atrox. 



Length of the largest specimen (a female), 162 mm. 



Station 3418. 660 fathoms. 3 males, 2 females (1 ovig.). 

 " 3424. 676 " 4 females. 



Sclerocrangon procax, sp. nov. 



Nearly related to S. agassizh Smith, from the Atlantic side of the conti- 

 nent. The rostrum of S. procax is longer than in S. agassizii, and inclined 

 upward at a much sharper angle ; the same is true of the antero-lateral spines 

 of the carapace. The most conspicuous difference is found in the anterior spine 

 of the median carina of the carapace, which is much longer and nearly erect -in 

 jS. procax. The two flagella of the first antenna in the male, S. procax, are 

 subequal, while in the male S. agassizii the outer flagellum is much longer 

 than the inner ; the scale of the second antenna, moreover, is narrower in the 

 former species than in the latter, and the terminal segment of the inner branch 

 of the second abdominal appendage in the male bears on its inner margin a 

 short blunt stylamblys, which is wanting in S. agassizii. In neither of these 

 species is this segment produced into a lobe at the base of its outer margin, as 

 it is in the more typical species of Sclerocrangon, e. g. S. ferox and S. atrox. 



Length, 49 mm. 



1 male j uv. 



2 males, 3 females. 

 2 females ovig. 

 1 female. 



