228 THE VOYAGE OF H.M.S. CHALLENGEE. 



Habitat. — Off Pernambuco, Station 120 ; depth, 675 fathoms. One specimen, 6|- 

 inches long. 



The height of the body is nearly one-fifth of the total length (without caudal) ; the 

 length of the head one-third. Bones of the head very thin and very easUy ruptured, like 

 all the other parts of the body. Head compressed, moderately deep, its depth at the 

 occiput being three-fifths of its length ; its upper surface longitudinally concave, the 

 width of the interorbital space being more than one-half of the longitudinal diameter of 

 the eye. Eye large, a little longer than deep, contained thrice and two-thirds in the 

 length of the head and equal to that of the snout. Infraorbital ring narrow, the broad 

 and large maxillary being separated from the orbit by a narrow strip of bone. Snout 

 wedge-shaped, with a pair of short and flat projections in front, each being formed by 

 the intermaxillary and toothed at its extremity. The cleft of the mouth is wide, the 

 maxUlary extending to below the hind margin of the orbit. Dentition very feeble, all 

 the teeth being minute and uniserial. The intermaxillary and maxillary are toothed 

 throughout their whole extent ; the teeth of the mandible are particularly minute, and 

 the series is interrupted close to the symphysis, the S5rmphysial portion being external to 

 the lateral portion, which is implanted on the upper edge of the bone. The vomerine 

 teeth are reduced to a pair of very small teeth in the middle of the bone. Palatine teeth 

 none, or reduced to a single tooth-like projection. 



Branchiostegals long, narrow, slender. Gills as in Bathytroctes macrolepis. Gill- 

 rakers long, lanceolate, closely set, 20 -f- 7 on the outer branchial arch. 



Vent nearer to the gill-opening than to the root of the caudal. Origin of the dorsal 

 fin somewhat in advance of the vent ; it is much longer than high, the length of the 

 anterior rays increasing to the sixth or seventh ray. Origin of the anal fin below the 

 anterior half of the dorsal, which it resembles in shape. Caudal fin deeply emarginate. 

 Pectoral inserted a short way above the lower profile, rather short and broad, about as 

 long as the eye. Ventrals broad, extending to the vent, their root being rather nearer to 

 the base of the caudal than to the extremity of the snout. 



Scales simple, cycloid, in about twelve longitudinal series above and below the lateral 

 line, between the dorsal and the ventral fins. Lateral line straight, running from the 

 upper end of the gill-opening along the middle of the tail, with rather small mucous 

 apertures. 



Colour, uniform black. 



A very small pointed osseous projection in front of the clavicular symphysis reminds 

 us of a similar peculiarity in the following genus, Platytroctes. 



