197 



openings very wide. Gillmembranes separate and free from 

 isthmus. Branchiostegals 7. Gillrakers long and slender. Verte- 

 brae 24. Bones of skull with well developed muciferous canals. 

 Moderate or large fishes, inhabiting sandy shores of tropical 

 seas and sometimes entering rivers, wanting in the Red Sea. 

 Only few specimens of these valued food-fishes extend into 

 temperate regions, probably with currents of tropical water. 



Key to the indo-australian genera of 

 Polynemidae. 



1. Lower lip only developed at coiner of mouth. Teeth 

 extending to the exterior part of jaws; 3 or 4 free 



pectoral filaments Ekiithcroncvia p. 197 



2. Lower lip well developed, but not continued to sym- 

 physis. Teeth in jaws not extending to the exterior; 



5 or more free pectoral filaments Polyncimts p. 200. 



I. Eleutheronema Bleeker. 



(Bleeker, Versl. Akad. Amsterdam XIV. 1862, p. 123). 



Elongate, somewhat compressed. Snout prominent. Eyes 

 covered by a gelatinous membrane. Mouth very large. Maxiilaries 

 scaly. Lips absent, except for the lower lip near corner of 



Fig. 64. Elciithcronevia tetrcdactylum (Shaw) X 'A- 



mouth. Small teeth which extend to the outside of the jaws. 

 Teeth on vomer, palatines and pterygoids. Praeoperculum ser- 

 rated behind. Anal of about same length as second dorsal, 

 with 15 — 17 rays and opposite to it. Pectorals with 3 or 4 

 free filaments only. Scales small. Gillopenings large, gillmem- 

 branes free from isthmus and from each other. 



Distribution: From British India to North and West 

 Australia. 



