I2 9 



its height from the posterior part. Eye large, by exception 

 telescopic. No barbel. Gape of mouth vertical or nearly so. 

 Origin of dorsal, which may be preceded by spines, in the 

 middle of the body or behind it, above or before that of 

 anal. Adipose fin low, totally or partly above hinder part of 

 anal, which may be divided. Ventrals small, below or before 

 origin of dorsal. Scales absent, if present large, thin and 

 exceedingly deciduous. Praeorbital, postorbital and ocular lumi- 

 nous organs single. Those on the mandibular symphysis, in the 

 branchiostegal membrane and on the body in groups : between 

 isthmus and ventrals in a ventral and more lateral series, 

 between ventrals and caudal in one series. Body without 

 smaller scattered luminous organs. No whitish punctiform 

 organs on fins. Small teeth in the jaws, on vomer present or 

 absent. Gillmembranes free from isthmus or attached to it, 

 they may also be delicately connected. 5 n branchiostegal 

 rays. 4 gills. Gillrakers well developed. Pseudobranchiae present 

 or absent. 



Synopsis of the genera. 



A. Body elevated, short, height i 1 ^' Anal short, II 17 

 rays. Pseudobranchiae present. 



1. Dorsal fin preceded by a forked spine. Teeth 

 on vomer. No abrupt ventral constriction between 



trunk and tail. Eyes normal. Anal not divided . Polyipnus p. 129. 



2. Dorsal fin preceded by a large triangular trans- 

 parent plate. No teeth on vomer. An abrupt 

 ventral constriction between trunk and tail. 



a. Space between trunk and tail filled by a 

 transparent integumentary plate. Eyes normal. 



Anal not divided Sternoptyx p. 132. 



b. Body hatchet-shaped, ventral constriction 

 without integumentary plate. Telescopic eyes. 



Anal divided Argyropelectis p. 134. 



B. Elongate, not elevated. Height 3%. Anal long with 



23 24 rays. No pseudobranchiae Valenciennellus p. 136. 



I. Polyipnus Giinther. 



(GUNTHER, Challenger Rep. Deep-sea fishes, 1887, p. 170). 

 Strongly compressed and elevated, but without abrupt ven- 

 tral constriction between trunk and tail, covered with large 

 but extremely thin, deciduous scales. Luminous organs before, 

 INDO-AUSTRALIAN FISHES II. 9 



