137 



than two-thirds the total length without the caudal. Diameter of the circular 

 eye nearly half the length of the head. 



Besides the spines connected with the fins and the pectoral and pelvic 

 arches, there are a pair of spines on the occiput, a pair on the nape, one at the 

 angle of the preoperculum and one at the posterior end of the mandible. 



The pectorals are short, being about half again as long as the eye. The 

 ventrals are very short and narrow. 



Arabian Sea : off Malabar coast, 912 to 931 fathoms. 



Distribution : Atlantic, Arabian Sea, "Western Pacific. 



Regd. No. y. 



Besides the " Investigator " specimen there is one of the " Challenger " 

 duplicates in the Indian Museum. 



Polyipnus, Giinther. 



Polyipnus, Giinther, Challenger Deep-Sea Fishes, p. 170 (1887) : Goods and Bean, Oceanic Ichthyology, p. 128. 



Form of the body as in Argyropelecus but without the abrupt ventral con- 

 striction between the body and the tail. Body covered with a thin silvery 

 burnished skin, like that of Argyropelecus, and with large extremely thin exces- 

 sively deciduous scales. Series of conspicuous luminous organs along the ventral 

 border of the head, body, and tail, and also on the sides of the head and belly. 

 A series of scutes form a serrature along the mid-ventral line from the pectoral 

 symphysis to the base of the caudal, the series being broken by the ventral and 

 anal fins. 



Mouth as in Sternoptyx, but the teeth in the jaws appear to be in more than 

 one series, at any rate anteriorly, and there are teeth on the vomer. 



Eyes large, lateral. 



Gill-opening wide, numerous very long gill-rakers on the outer side of the 

 first branchial arch. Pseudobranchia? present. Branchiostegals six (?) 



Dorsal fin beginning about the middle of the body, rather short, preceded 

 by a small bifurcate spine but not by any large triangular osseous plate. Anal 

 rather short. Caudal forked. Adipose dorsal present. 



Pectorals well developed, situated near the ventral profile : ventrals small : 

 the humeral and pelvic symphyses project in the middle line of the belly, but 

 not so strongly as in Argyropelecus. 



An air-bladder. 



Distribution. Tropical Pacific, Andaman Sea. 

 18 



