182 A. Alcock — Account of the Deep Sea Collection. [No. 4, 



in a broad creamy white ring, on the dorsal fin between the 20th and 

 30th rays or a little beyond: anal jet black with a milk-white border. 



Length of type 5"25 inches. 



Bay of ^Bengal, 128 fathoms. 



PHYSOSTOMI. 

 Family, Scopelidae. 



Odontostomus, Cocco. 



6. Odontostomus atratus, n. sp., PI. IX Fig. 4. 



The extreme length of the square, high, compressed head is a little 

 more, and the greatest height of the compressed tapering body is a 

 little less, than one-fourth of the total, caudal included. 



The snout has the form of a pointed wart beyond which the upper 

 jaw projects, the lower jaw again projecting beyond the upper. 



The eyes, which are situated about a diameter apart, near the top 

 of the bead, have their major diameter obliquely vertical, and are capa- 

 ble of such strong rotation inwards as to bring the visual axis obliquely 

 upwards, the orbit being walled in laterally by a stout but transparent 

 fold of skin .in its lower half. 



The cleft of the mouth extends almost to the posterior edge of the 

 operculum : the premaxillee are armed with a series of close uniform 

 serrations for the most part pointing forwards, the vomer bears on each 

 side a sabre-shaped depressible fang nearly half as long as the head, 

 the palatines have each an exactly similar fang succeeded by a row of 

 close serrations, and the mandible has on each side a distant series of 

 similar fangs of unequal size, the largest of them however being hardly 

 half the length of those on the vomer and palatines. 



Gill-cleft extremely wide and high : four gills with wide laminea 

 and gill-rakers inconspicuous or absent : pseudobranchise large. 



Body covered with a glandular scaleless skin in which the lateral 

 line appears in spirit as a white streak. Rows of white dots (luminous 

 organs ?) exist along the free border of the preoperculum and the inner 

 border of the broad boat-shaped mandible. 



The dorsal fin lies altogether within the anterior half of the body ; 

 the anal begins about half a head length behind the vertical through 

 the last dorsal ray, and extends to the rudimentary basal rays of the 

 forked caudal. The large pectorals arise close to the ventral profile, 

 almost in the same plane with the veutrals, the bases of which they 

 touch when laid back. The veutrals arise under the middle of the 

 dorsal. 



Colour in spirit, jet black. 



Length 3*5 inches. 



Bay of Bengal, 573 fathoms. 



