CLASS IV. ORDER IV. 87 



scales small, deciduous ; air-bladder hard or bo- 

 ay- 



ANABLEPS, head subdepressed ; mouth termi- 

 nal ; teeth small, on the jaws ; eyes protuberant, 

 with double pupils ; gill-membrane six-rayed. 



AMJA, head bony, naked, rough, with visible 

 sutures ; teeth both in jaws and palate, close-set, 

 sharp, numerous ; cirri or beards two, near the 

 nostrils ; gill-membrane twelve-rayed ; body sca- 



Jy- 



SILURUS, head large, depressed ; mouth wide,, 

 bearded by longHentacula 5 body lengthened, na- 

 ked ; first ray of the pectoral-fins, or of the first 

 dorsal-fin, toothed backwards. 



PLATYSTACUS, habit as Silurus ; mouth be- 

 neath, bearded with cirri; body scaleless, depress- 

 ed ; tail long, compressed. 



LORICARIA, habit as Silurus ; body mailed. 



SALMO, (salmon, trout,) head smooth, compress- 

 ed ; tongue cartilaginous ; teeth both in the jaws 

 and on the tongue ; gill -membrane from four to ten- 

 rayed ; body compressed, furnished at the hind 

 part with an adipose fin. 



ACANTHONOTUS, body elongated, without dor- 

 sal-fin ; spines several on the back and abdomen. 



FTSTULARIA, (tobacco-pipe, trumpet-fish,) snout 

 cylindric ; mouth terminal ; body lengthened ; 

 gill-membrane seven-rayed. 



Esox, (sea-pike, gar-fish,) head somewhat flat- 

 tened above ; mouth wide ; teeth sharp, in the 

 jaws, palate and tongue ; body lengthened ; dor- 

 sal and anal-fin (in most species) near the tail and 

 opposite to each other. 



POLYPTERUS, gill-membrane single-rayed ; dor* 

 sal-fins numerous. 



