157 



Key to the Indian species of the genus Bathypterois. 



I. Ventral edge of the caudal peduncle not notched : — 



1 . Lowermost caudal and ventral rays enormously prolonged, nearly 3 



times as long as the head in the adult, longer in the young ... B. Guntheri. 



2. Lowermost caudal and ventral rays moderately prolonged, the former 



about once aud a half, the latter not quite twice the length of the head B. insular um. 

 II. Ventral edge of the caudal peduncle curiously notched : the outer ventral rays 



slightly, the lowermost caudal rays very slightly prolonged ... ... B. atricolor. 



126. Bathypterois Guntheri, Alcock. 



Bathypterois Oiintheri, Alcock, Ann. Mag. Nat. Hist., Dec. 1889, p. 450, and August 1891, p. 129: Illustra- 

 tions of the Zoology of the Investigator, Fishes, pl. VII. fig. 6. 



B. 12. D. 13. A. 11. P. 2/6/5. V. 7-8 L. lat. circ. 55. 



Body elongate and compressed, its height about one-sixth of the total, 

 without caudal. Head contained nearly three and a half times in the same 

 measure ; depressed, flat-crowned, nearly as broad as deep. Snout broad, de- 

 pressed, rounded, duck-bill shaped, with a median intermaxillary notch, into 

 which a strong recurved projection of the very prominent mandible fits ; its length 

 one-third that of the head; its surface with numerous large pores. A wide 

 mucous channel with a line of large pores along the under surface of the broad 

 mandible. Eyes minute, situated near the middle of the maxilla, close to its 

 edge, a snout-length apart ; the orbital margins rounded and inflated. Interorb- 

 ital space nearly flat from side to side. Nostrils small, superior, far in advance 

 of the eye. 



Cleft of mouth extremely wide, slightly oblique ; the maxilla, which has a 

 dilated, abruptly-truncated, hinder end, is nearly two-thirds the head-length. 

 Villiform teeth in broad bands on the outer edges of the strong jaw-bones, and 

 in a minute patch on each side of the expanded vomer. 



Gill-cleft reaching to the fore end of the isthmus ; gill-lamina? broadish ; 

 gill-rakers numerous, close-set, long, bristle-like, except on the fourth arch. 



Body and head, except the jaws and front part of the vertex of the snout, 

 covered with large, thin, smooth scales, those on the sides of the head rather 

 deciduous, those on its crown enlarged. 



The interradial membrane of all the fins except the caudal is covered with a 

 thick, black, velvety, deciduous integument. The dorsal begins a little in 

 advance of the middle line, and is just entirely in advance of the anal, the two 

 fins being of nearly equal extent and height. A very small adipose dorsal in the 

 posterior half of the tail. Caudal large and deeply forked ; its lowermost ray 

 rigid, prolonged, curved, with a spatulate tip, the total length of the ray from 

 base to tip being nearly two-thirds that of the rest of the body. 



