Fishes of the Western North Atlantic 197 



nates considerably in front of the origin of the pelvics, whereas in all the others it origi- 

 nates over or considerably behind the latter.^^ In this respect, and in others also, it is so 

 aberrant that we have recently proposed the new genus Cephalurus for it," based on study 

 of a specimen from the original series. 



Among the remaining scyliorhinids eight clearly distinct species from various parts 

 of the world are set apart by the facts that labial furrows, well developed on the lower 

 jaw, do not extend around the corner of the mouth or onto the upper jaw, and that the 

 upper lip is expanded to close over the lower near the corner of the mouth. It was for a 

 member of this group (caniculus Linnaeus, 1758) that the earliest scyliorhinid genus was 

 proposed {Scyliorhinus Blalnville, 18 16). It is true that in this instance generic diagnosis, 

 based primarily on the morphology of the labial furrows, runs counter to the grouping that 

 might be based on the details of the nostril, and on the relationship of the latter to the 

 mouth, for among the species with well developed lower labial furrows and no upper 

 furrow are some in which the anterior margins of the nostrils reach to the mouth but 

 others in which they fall short of the latter, and a similar range of variation, based on 

 whether or not the nostril is connected to the mouth by a shallow groove, exists among 

 them. But the varietal series are so continuous in these respects that nothing would be 

 gained by abandoning the labial furrows in favor of the nostrils as the primary character. 

 Therefore, it seems logical to use the labial furrow rather than the nostrils as the generic 

 criterion, except for two South African species, Poroderma fantherinum Muller and 

 Henle, 1841," and P. marleyi Fowler, 1934,'^ in which the anterior margin of the nos- 

 tril is extended as a long tapering barbel. For these a separate genus seems appropriate. 

 Unfortunately, however, the old name Poroderma is not available for them, because its 

 type species" lacks the barbel, and is in fact a typical Scyliorhinus. But there is no need to 

 coin a new name, Fowler^^ having proposed Conoporoderma as a subgenus for the species 

 with barbels. 



In some of the members of the family still to be considered the labial furrows extend 

 from the lower jaw around the angle of the mouth onto the upper jaw, while in others they 

 are wholly lacking. The latter category includes the peculiar Swell Sharks, which are able 



Nardo (Atti Riun. Sci. Ital., 1 841 : 312) from the Mediterranean may be Pentanchus-\\ke, and Fowler (Bull. U.S. 

 nat. Mus., 100 [/j], 1941 : 26) retains it provisionally among the Scyliorhinidae. But it does not seem likely that 

 the combination of characters credited to it by Nardo (single dorsal fin, but with only 5 gill openings and no 

 spiracle) actually applies to any existing shark. For a history of the case, with suggestions as to what the speci- 

 men in question may actually have been, see Fowler, 1941; also Doderlein (Man. Ittiol. Medit., 2, 1881: 82). 

 I 2. Another species with first dorsal far forward, classed in this family by Garman {Proscyllium habereri Hilgen- 

 dorf, 1904), is placed among the Triakidae by us. 



13. See Bigelow and Schroeder (Copeia, 2, 1941 : 73) for discussion and detailed description. 



14. Usually credited to Andrew Smith, 1837, but Smith (Proc. zool. Soc. Lond., 1837: 85) listed it only by name; 

 the earliest account of it was by Muller and Henle (Plagiost., 1841 : 13). 



15. Fowler (Proc. Acad. nat. Sci. Philad., ^5, 1934: 234) has pointed out that it was actually a specimen of this 

 species that he pictured earlier (Proc. Acad. nat. Sci. Philad., 77, 1925 : 188) under the name Scyliorhtnus recant. 



16. Porodertna africanum A. Smith (Proc. zool. Soc. Lond., 1837: 85) equals Squalus africanus Gmelin, 1789. 



17. Proc. Acad. nat. Sci. Philad., 6$, 1934: 234. 



