98 



filaments, of which the inner is much the longer, reaching beyond the origin of 

 the anal fin. 



A bimch of about six slender ca?ca situated above the pylorus. 



Colours in the fresh state : — uniform chocolate ; fins blackish ; throat and 

 belly black, owing to the pigmentation of the peritoneum. 



The largest specimen is just over four inches long. 



Bay of Bengal, off Ganjam coast, 1310 fathoms. 



Regd. No. 12829, 12830. 



Named after Rear- Admiral Sir John Hext, R. N., formerly Director of the 

 Royal Indian Marine, who was always a good friend to the Zoological depart- 

 ment of the " Investigator." 



Diplacanthopoma, Giinther. 



Diplacanthopoma, Giinther, Challenger Deep-Sea Fishea, p. 115 : Goode and Bean, Oceanic Ichthyology, p. 318. 



Body elongate, compressed, covered with small thin imbricate scales. Head 

 broad, somewhat depressed, covered with a thick, glandular, scaleless skin, 

 sharply defined from the scaly skin of the trunk : its bones firm. 



Lateral hue indistinct and incomplete (or absent?). 



Snout broad, depressed, slightly overhanging the lower jaw ; without barbels. 

 Mouth wide : villiform teeth in bands on the jaws and palatines and in a A-shaped 

 band on the vomer. 



Eye of moderate size. 



Gill-openings wide : operculum with two radiating ridges each ending in a 

 spine : free edge of preoperculum rounded, unarmed. Eight branchiostegals (in 

 two species), but the branchiostegal membranes are so thick that the rays cannot 

 be counted without reflecting the skin. No pseudobranchiaa. 



Dorsal and anal fins confluent with the caudal. The ventrals arise close 

 together a short distance behind the clavicular symphysis : each consists of a 

 single filament, which sometimes is made up of two (or more ?) rays intimately 

 fused together throughout their extent. 



Air-bladder present. No pyloric cosca. 



In one of the three known species of this genus the female is viviparous, and 

 in another species the male has a peculiarly elaborate penis. 



Key to the species of Diplacanthopoma. 



I. The two spines of the operculum are hidden in loose skin: length 



of the adult female about six inches ... ... ... D. raniceps. 



II. The two opercular spines project freely : — 



1. Adult female about four inches long ... ... D. brachysoma. 



2. Adult female about fifteen inches long ... ... D. Rivers-Andersoni. 



