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



The form of this fish is very elongate, depressed from the neck forwards, somewhat 

 cylindrical about the middle and rather compressed behind. The greatest depth of the 

 body, below the origin of the dorsal fin, is about twice the depth of the caudal peduncle, 

 and one-ninth of the total length, without caudal. The head is greatly depressed behind, 

 twice as broad as deep, its length being contained three times and three-fourths in 

 the total length, without caudal. Snout depressed and long, the hind margin of the eye 

 beino- in the middle of the length of the head ; eye rather large, one-seventh of the length 

 of the head, partly directed upwards, and separated from the intermaxillary by the 

 exceedingly narrow chain of infraorbital bones. The mouth is exceedingly wide, the 

 length of the mandible being nearly three-fourths of that of the head ; and the jaws are 

 powerful, especially the lower, which is greatly expanded on the lower aspect of the 

 head. 



Teeth numerous, unequal in size, generally curved, and with a more or less distinctly 

 barbed point (see fig. A'"). Almost all are depressible in the longitudinal axis of the head. 

 In the upper jaw they form a broad band with the largest teeth along the inner margin 

 (fig. A'). The mandibulary band is still broader (fig. A") ; in fact, it consists of two 

 narrower bands between which the intermaxillary teeth are received. The vomerine and 

 palatine teeth form one continuous biserial row, close and parallel to the intermaxillary. 

 These teeth slightly exceed those of the jaws in size, at least anteriorly, but gradually 

 decrease in length backwards. The row consists of two series, those of the outer series 

 being shorter and fixed. Also the basibranchials are armed with small curved teeth, 

 uniserial in front and biserial behind. Patches of small teeth take the place of gill- 

 rakers. 



The upper side of the head, the snout, and the branchiostegal membrane are naked, 

 the cheeks and the gill-cover scaly. The nostrils are a pair of small ojDenings, close 

 together, but separated by a short flap ; they are about midway between the eye and the 

 end of the snout, and quite at the upper side of the head. The muciferous channels are 

 narrow with small but distinct openings. 



Branchiostegals long and flexible ; the gill-openings extremely wide, extending from 

 the upper end of the gill-cover near to the symphysis of the lower jaw; the left branchio- 

 stegal membrane overlaps the right in front. 



The dorsal fin is higher anteriorly than posteriorly, and higher than the body 

 underneath, the length of the second ray being more than one-half of that of the head ; 

 this fin occupies the middle of the length of the fish, its distance from the root of 

 the caudal being equal to that from the end of the snout. The anal fin commences 

 shortly behind the vertical from the last dorsal ray, and is higher in front than behind. 

 Caudal fin emarginate, with a great part of its basal portion covered with scales. 

 Pectoral long, extending to the ninth dorsal ray ; its base is narrow, and when in 

 use this fin assumes a horizontal position much like the ventral. Ventral fin 



