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



small. The anterior nostril niucli smaller than the posterior and about midway between 

 the posterior and the extremity of the snout. Vertical fins confluent ; ventrals close 

 together, close to the humeral symphysis, each composed of two subequal filaments. 



Gills four, with very short laminae, but with long stiff' gill-rakers on the first 

 branchial arch. Pseudobranchi^e rudimentary. 



Porogadus gracilis (PI. XVI. fig. B). 



Bathynedes gracilis, Giinth., Ann. and Mag. Nat. Hist., 1878, vol. ii. p. 21. 



Head and body low, rather compressed ; tail produced into a long filament. The 

 greatest depth of the body is on a level with the root of the pectoral, and is two-sevenths 

 of the length of the trunk. The length of the head is nearly one-half of the same 

 length. Eye of moderate size, its diameter five and a half times in the length of the 

 head, and two-thirds of that of the snout and of the width of the interorbital space, 

 which is somewhat convex. The posterior nostrils are very wide and separated from 

 the eye by a small spinous projection of bone. The muciferous channel of the infra- 

 orbital ring shows in its course five or six wide sinuses, that of the prseoperculum four 

 or five. The integument of the head being very thin, underlying projections of the 

 bone appear in preserved specimens as small prominent spines above the posterior 

 portion of the eye ; on the shoulder there is a single short spine. Prseoperculum 

 without spines. Mouth very wide, extending far behind the eye, the extremity of the 

 maxillary much dilated. The teeth form narrow bands, that of the vomer is A-shaped, 

 with the two arms straight. The dorsal fin commences above the root of the pectoral, 

 its rays being of moderate length, but longer than those of the anal. Pectoral with 

 feeble rays, tapering, as long as the head exclusive of the snout. Each ventral is 

 composed of a bifid filament, the longer part of which extends backwards as far as the 

 pectoral. 



Scales very thin, cycloid, small, with the exception of some (about seven), which 

 form a series running from the upper end of the gill-opening towards the dorsal fin ; 

 these are about three times the size of the others. About twenty-four may be counted 

 in a transverse series running from the vent to the dorsal fin. 



Outer branchial arch with sixteen long and slender gill-rakers, the longest of which 

 are about five times as long as the laminae. Of pseudobranchise only two minute lobules 

 can be distinguished. 



Colour light brownish, head and abdomen black. 



Habitat. — A single specimen, 9 inches long, was obtained at Station 184, south of 

 New Guinea, at a depth of 1400 fathoms. 



