Chcetodon* gangetic pishes. 123 



proportion to both height and length, and is somewhat of a 

 quadrangular form, sloping very suddenly both before and be- 

 hind, and its height being little short of its length. Its colours 

 vary much in different individuals ; but in all cases the sides, so 

 far down as the pectorals and lower part of the tail fin, are co- 

 vered with fine round black spots, larger than the spaces that 

 intervene. The most common colour of the adult fish is blue, 

 with a tinge of green on the back, and a silvery gloss on the 

 sides, especially on their lower parts ; and the hinder fins are 

 yellow. In many individuals, however, the back is green, and 

 the lower parts ash-coloured, changing to purple, with a gloss 

 of silver. In young individuals, again, the whole is green, with 

 a bright golden gloss. The eyes are black, with a narrow 

 golden ring surrounding the pupil. 



The head is small, oval, and blunt, with a convexity between 

 the eyes. The mouth is small, and extends horizontally back 

 from the extremity of the head. The jaws are nearly equal in 

 length. The lips are fleshy, and without bones. The palate is 

 smooth. The nostrils are in the middle, between the eyes and 

 jaw, each containing two apertures, of which the foremost is cir- 

 cular and open, and the hindmost is oblong, and covered by a 

 reflected membrane. The eyes are high, on the sides of the 

 head, are of moderate size, and circular, with oval pupils, point- 

 ing forward. The gill-covers have minute scales, end in a point 

 behind, and on each side leave a large aperture. Each consists 

 of two plates, and exposes to full view its membrane, which con- 

 tains four rays. 



The fore part of the back descends very rapidly on the head. 

 Behind it contains a furrow for receiving the prickles of the fin. 

 The belly forms an arch less prominent than the back. The 

 tail, both above and below, slopes very rapidly near the end, 

 and before the slope has a furrow for receiving the prickles of 



