Plearonectes. gangetic fishes. 131 



tendril. The mouth is behind the nose, is small, and, when 

 shut, forms a curve. The jaws do not protrude when open, 

 and contain no teeth. The lips are fleshy ; the upper one ra- 

 ther the longest and sharp ; the under one has a slight notch 

 at the end. The palate and tongue are smooth, and the latter 

 is sharp. 1 can observe no nostrils. The eyes are convex and 

 small, and even the irides are covered with scales. The gill- 

 covers are simple, scaly, and rough, move freely, and their pos- 

 terior edge forms a kind of arch, leaving a small opening at 

 the throat, and concealing their membranes, each of which con- 

 tains four rays. 



The lateral line is straight, and in the middle. The vent is 

 far before the middle. The scales are minute, oblong, and in- 

 dented at the end with five or six little spines. 



There are only five fins, those of the back, tail, and vent, being 

 completely united into one, which extends from the vent to 

 within less than a quarter of an inch from the mouth ; nor are 

 the parts distinguishable. The rays are shortest at both ter- 

 minations, and lengthen gradually to the centre of the tail, 

 which is rather sharp. The whole fin is scaly, and has one 

 hundred and fifteen undivided rays, of which sixty-four are 

 above, and fifty-one below. The pectoral fins are near the 

 vent, blunt and minute, each containing five hair-like rays, of 

 which the second is the longest. The ventral fins are very 

 small, surround the vent, and approach very near, each con- 

 taining four rays. 



XII. Genus. — Achirus. 

 Fishes of the fourth order, with both eyes placed on one 

 side, and destitute of pectoral fins. 



