169 



in front. A series of small teeth in the premaxilla? mandibles and palatines, and 

 sometimes on the vomer. Eye large. 



Gill-openings wide, the opercles large and thin. Six branchiostegals. Gill- 

 rakers numerous and rather long. 



Dorsal and anal fins nearly equal and opposite, placed far back, in the 

 posterior half of the body. Caudal forked. Pectorals and ventrals well deve- 

 loped, but rather small. 



Distribution : Atlantic ; Mediterranean ; Arabian Sea and Bay of Bengal ; 

 Western South Pacific. 



Key to the Indian species of Alepocephalus. 



I. The maxilla reaches a little beyond the anterior border of the orbit, and the 

 snout is more than a fourth the length of the head : tlie anal fin begins well 

 behind the middle of the body (measured with the caudal) : — 



1. Eyes of adult more than a diameter apart, and between a fifth and a 

 sixth the length of the head : the gill-membranes overlap each other 

 broadly: 9 pyloric cseca ... ... ... ... A.bicolor. 



2. Eyes of adult less than a diameter apart, and between a third and a 

 fourth the length of the head : the gill-membranes overlap slightly: 14 



pyloric casca ... ... ... ... ... A. Blanfordi. 



II. The maxilla reaches nearly to the posterior border of the orbit, and the snout 

 is less than a fourth the length of the head : the anal fin begins exactly in 

 the middle of the body : 4 pyloric cseca ... ... ... ... A, edentulus. 



136. Alepocephalus bicolor, Alcock. 



Alepocephalus bicolor, Alcock, Ann. Mag. Nat. Hist., August, 1891, p. 133 : Illustrations of the Zoology of 

 the Investigator, Fishes, pl. IV. fig. 2. 



B. 6. D. 21. A. 28. P. 10. V. 8. L. lat. 62. L. tr. 18. 



Length of the head slightly more than a fourth, height of the body nearly 

 a fifth the total without the caudal. 



The length of the obtusely- pointed depressed snout is contained about 

 3.- times in that of the head. The eyes, which converge anteriorly, are between 

 one-fifth and one-sixth of the head-length in diameter, and are more than their 

 own diameter apart. The large nostrils are situated close together immediately 

 in front of the eye. 



Mouth-cleft slightly oblique; the maxilla reaches just behind the vertical 

 through the anterior border of the orbit. A row of small teeth in each jaw and 

 on the palatines. 



Gill-openings very wide, the membranes entirely separate and overlapping 

 broadly ; a great part of the gill-cover is formed by the broad flat branchiostegal 

 rays, which are uncovered by the opercle from their very bases ; the opercular 

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