38 DEEP-SEA FISHES OF THE ATLANTIC BASIN. 



margin. The upper jaw extends a little behind the vertical from the posterior margin of 

 the pupil; the lower jaw is shorter and included by the upper, and is nearly one half as long 

 as the head. The width of the cranium between the orbits is one-seventh of the length of 

 the head, and behind the orbits, more than one-third. The insertion of the dorsal is above 

 the vent; the length of its base is twice the diameter of the eye. The anal base is under 

 the anterior portion of the dorsal, and the length of its base is about three fourths that of 

 the dorsal. The caudal flu has its median rays as long as the diameter of the eye, and the 

 external rays at least one-fifth of the total length of the fish. The pectoral commences at 

 a distance from the snout equal to one-fourth of the length of the body. The rentrals are 

 inserted considerably behind the middle of the length (0.57), and appear to have been at 

 least as long as the diameter of the orbit. 



Radial formula: D. 17; A. 17; scales 9, 67, 12. 



The type of this species (No. 33311, U. S. N. M.) was obtained by the Albatross from 

 station 2035, in 30° 26' N. lat, 70° W. Ion., at a depth of 1,362 fathoms. 



The preliminary description published by Gill was very brief. The fuller description 

 here presented was prepared by him at the time of his original studies. 



Alepocephalu8 niger (Figure 42) is a small-scaled black form inhabiting the seas north of 

 Australia, and obtained by the Challenger at a depth of 1,400 fathoms. 1 



ALEPOCEPHALUS BAIRDII, Goode and Bean. (Figure 47.) 



Alepocephalut) Bairdii, Goode arid Bean, Proc. U. s. Nat, Mus., n, 1879, 55 (with full measurements of 

 type). — Jordan and Gilbert, Bull. xvi. 1 T . s. Nat. Mus., 257. — Jordan, Cat. Fish. N. A., 34. — GOnther 

 Challenger Report, XXII, 224. 



Body comparatively elongate, somewhat compressed, its greatest height, at a point mid- 

 way between pectoral and ventral insertions, contained 5J times in its length to the origin 

 of the middle caudal rays, its greatest width equal to one tenth of total length, the least 

 height of tail contained 11 times in length of body. 



Scales large, thin, oblong, triangular at the free end, those at the base of the anal fin 

 having the free end more produced than the others. Sixty live scales in the lateral line, 

 seven rows between it and the origin of the dorsal, eleven between that of the anal and the 

 lateral line. Scales extend for a short distance upon the bases of the dorsal and anal tins. 



Head moderately compressed, snout subcorneal, the lower jaw included. The length of 

 the head is contained 4^ times in length of body, slightly exceeding twice the length of 

 the lower jaw. Width of the head equal to the length of the operculum and very slightly 

 less than that of the upper jaw. Width of interorbital area half of the least height of tail. 

 Length of snout half that of the mandible, which is one-ninth of the total length. Diam- 

 eter of orbit equal to length of snout. 



Dorsal inserted directly above the vent, slightly in advance of the anal and at a dis- 

 tance from the snout nearly equal to two-thirds of the total length of the body. 



Length of longest ray of dorsal one-half that of the postorbital portion of the head. 

 The distance of the anal from the snout is almost 3 times the length of the head, its 

 first ray being about under the fourth ray of the dorsal. Its length of base is greater than 

 that of the dorsal by one fifth of the length of the latter; its longest ray slightly exceeds 

 the longest of the dorsal. 



Middle caudal rays equal in length to longest ray of anal, the external rays somewhat 

 more than twice as long. 



Distance of pectoral from snout 3 times as great as the least height of the tail; its 

 length one-tenth of total length and equal to width of body, reaching to ninth row of scales. 



Distance of ventral from snout equal to twice the length of the head, its length slightly 

 greater than that of middle caudal rays. 



Radial formula: B. 0; I). 22; A. 25; C. 19; P. 12; Y. 1, 9. Pyl. Caec. 15. 



1 Challenger Report, xxn, 224, pi. lvi, fig. B. 



