144- Mr. A. Alcock on 



Teeth of upper jaw erect, triangular, very acute, in two 

 series \ teeth of lower jaw acute, very oblique, in a single 

 series. 



The posterior borders of all the fins are frayed or fringed, 

 this not being due to abrasion. The angle of the pectoral is 

 rounded ; the extremity of the ventral is almost in the perpen- 

 dicular with the after limit of the base of the second dorsal. 

 The dorsal spines (measured obliquely as they stand) are not 

 much more than half the greatest height of their fins, but their 

 points project well beyond the skin ; the second dorsal is a 

 little larger than the first. 



Scales minute, acutely tridentate. 



Colour uniform jet-black. 



A single specimen, 10 inches long, from off the Travancore 

 coast, 430 fath. 



Named in memory of Captain Daniel Ross, who, according 

 to Sir Clements Markham, was the first Indian "Marine 

 Surveyor-General" (182-3-1833) who introduced a really 

 scientific method into marine surveying in India. 



PLAGIOSTOMATA BATOIDEI. 

 Family Torpedinidae. 



Bentuobatis, gen. no v. 



The whole animal invested in a loose, soft, naked, glan- 

 dular skin. 



Tail very distinct from the oval disk and ivithout distinct 

 lateral folds. Two dorsal tins on the tail ; caudal fin well 

 developed. 



Nasal valves confluent into a quadrangular curtain. 



Teeth flat, rhomboidal, with the posterior angle acutely 

 produced. 



Spiracles large, situated immediately behind the incon- 

 spicuous and quite rudimentary eyes. 



A large electric organ between the head and either pectoral 

 fin. 



This curious blind torpedo differs from all other members 

 of the family in having the eyes quite rudimentary and in the 

 absence of lateral folds of skin on the tail. In general form 

 it resembles Narcine, though the disk is not quite so broad. 

 The teeth, like those of Discopyge, have the posterior angle 

 produced, but more acutely than in Discopyge, judging from 

 Tschudi's figure. 



