Pimelodus. gangetic fishes. 199 



The eyes are high and far back. Their longer diameters, as well 

 as those of their pupils, are horizontal. Each cover of the gills 

 consists of one smooth plate, ending behind in a point ; and 

 they do not conceal their membranes, which are thick. Each 

 contains five rays. There is a slit under the throat. 



The back slopes with the same curve as the head, and, be- 

 fore the first fin, has a bony plate, waved like that on the head. 

 It sends a branch on each side of the fin. The sides slope out- 

 ward toward the belly, and each above the shoulder-blade, which 

 is exposed, has an oblong tumour. The lateral line descends 

 from the shoulder to the end of the tail, which terminates in a 

 notch. Perpendicular to each lateral line are several single 

 rows of pores. The vent is behind the middle. 



The fins are covered with a thick skin. The first dorsal 

 slopes much behind with a concave edge, terminated by two 

 sharp points. The first of its rays is a very short thick bone ; 

 the second is a strong prickle, smooth on the edges, and termi- 

 nated by a substance like whalebone ; the others are branched. 

 The hinder fin is almost triangular, and nearly as long as that 

 behind the vent. The pectoral fins are low, longer than the 

 head, and sharp above. Each contains ten rays, of which the 

 first is a strong prickle, barbed behind, and ending in a sub- 

 stance like whalebone. The ventral fins are much smaller 

 than the pectorals, and each contains six rays, of which the 

 first is undivided. The fin behind the vent slopes each way 

 from the fifth ray, before very suddenly, behind more slowly ; 

 but it terminates there in a point. Its first five rays are undi- 

 vided. The lobes of the tail fin are sharp, deeply divided, and 

 contain eighteen distinct rays, besides compacted ones. 



29th Species. — Pimelodus mangois. 

 A Pimelodus with the tail fin divided into two unequal lobes; 



