EEPORT ON THE DEEP-SEA FISHES. 171 



length, without caudal. The head is much higher than long, its length one-third of the 

 total ; eye large, two-fifths of the length of the head. Mouth vertical, snout extremely- 

 short. Intermaxillary narrow, and, although it does not entirely form the margin of the 

 upper jaw, it reaches as far as the cleft of the mouth, when the gape is open to its fullest 

 extent. The maxillary is a broad lamelliform bone ; the lower two-fifths of its anterior 

 margin remain free from the intermaxillary, and show a very obscure and rudimentary 

 denticulation. The teeth in both jaws are minute, and appear to form anteriorly an 

 extremely narrow band, and laterally a single series ; vomerine teeth present, and similar. 

 The upper part of the head is much compressed, narrow, hollow, and bordered on each 

 side by a serrated ridge. The two ridges slightly converge behind, and are continued as 

 a pair of humeral ridges, which terminate behind in a strong and acute spine. On the 

 side of the head the ridges of the prseoperculum are very distinct, the posterior and 

 inferior meeting at a right angle, and the angle being armed with a slender claw-like 

 spine, which points downwards. Also the lower margin of the mandible is finely serrated, 

 and terminates behind in a short and obtuse spine. 



Nostrils in front of the upper part of the eye, separated by a very narrow bridge of 

 skin, the posterior being much wider than the anterior. 



Branchiostegals five. The gill-membranes overlapping the isthmus free. Gill-rakers 

 rather numerous, closely set, long and slender ; pseudobranchise present. 



The dorsal fin is preceded by a minute forked spine, and composed of eleven soft rays. 

 A wTll-developed adipose fin, which is about half as long as the rayed dorsal, occupies the 

 middle of the space between dorsal and caudal. Anal fin with fourteen rays. Caudal fin 

 composed of some thirty-five rays, some of which occupy the ujiper and lower edges of the 

 tail. Pectoral inserted low down on the side, composed of about fourteen very slender 

 rays, and pointing forwards, not backwards. The lower edge of the abdomen is convex 

 and denticulated, the ventrals being inserted in front of the vent, close together, and in a 

 vertical position. None of the scales have been preserved, but to judge from the ^iouches, 

 which are distinctly visible, they must have been large, and numbering perhaps thirty- 

 two, in a series along the middle of the side. 



The luminous organs have reached in this fish an extraordinary degree of development 

 as regards size and number : — 



1. A series of six, pearl-coloured, oblong organs runs on each side of the isthmus to 

 the root of the pectoral fin. 



2. A series of ten along each side of the ventral edge, from the humeral symphysis to 

 the ventral fin. 



3. A series of five, which are rather irregularly arranged, occupies a position higher 

 up the side above the level of the pectoral. 



4. Two isolated organs are placed still higher up the side of the trunk, but below the 

 middle line. 



