54 gangetic fishes. Order IV. 



The first fin of the back has five rays shorter than those of 

 the second, which slopes down toward the tail. The -pectoral 

 fins are sharp above, and each contains ten rays. The ventral 

 fin contains five, and the fin behind the vent, which slopes 

 down towards the tail, has ten rays. The tail fin ends in a 

 slight crescent, and contains about eighteen rays. 



12th Species. — Gobius nunus. 



A gobius with five rays on the second fin of the back. 



This fish is found along with the former in the river below 

 Calcutta, and is still more minute. It is of a green colour on 

 the back, and below shines like silver. It has six irregular 

 black belts ; one passing through the eyes, a second on the 

 gill-covers, the third at the pectoral fins, the fourth at the vent 

 fin, the fifth behind the second back fin, and the sixth at the 

 end of the tail. 



The head is oval and wide. The mouth descends backward, 

 the under yaw being the longest. The teeth, owing to the mi- 

 nuteness of the creature, are scarcely discernible. The eyes 

 are far forward. 



The lateral lines are scarcely distinguishable. 



The first back fin contains six undivided rays. The pectoral 

 fins are sharp-pointed, and each contains ten rays. The ven- 

 tral contains the same number. There are seven in the anal 

 fin ; and that of the tail, which is rounded, contains about 

 eighteen. 



III. Genus. — Cheilodipterus. 



Fishes of the fourth order with the ventral fins distinct, with 

 two fins on the back, and with the gill-covers quite entire and 

 unarmed, leaving a large aperture on each side. 



These fishes, perhaps, should have been considered as be- 



