Cyprinus. gangetic fishes. 257 



the mouth, but this organ is often altogether destitute of these 

 appendages. 



This very numerous class of fishes has been usually subdi- 

 vided from the form of the tail fin, and from the absence or 

 presence of fewer or more numerous tendrils ; but these or- 

 gans, in several species, are so minute as to render it uncertain 

 whether some individuals of the same species have them or 

 not ; and the fin of the tail, in all the Gangetic species except 

 one, is divided into two lobes, more or less distinct. Besides, 

 this arrangement brings together species that have little gene- 

 ral resemblance. I have, therefore, been under the necessity 

 of adopting other divisions, which, indeed, bring together the 

 species most nearly allied ; but, I must confess, that some of 

 the divisions are not distinguished by very strictly defined 

 characters. In order to save repetitions in the specific charac- 

 ters, I have given each division a common name, derived 

 generally from some native generic appellation. 



Besides the circumstances mentioned in the generic charac- 

 ter, the species of Cyprinus found in the Ganges, except in a 

 few cases that will be specified, have in common the following 

 marks : 



The head is devoid of scales, and has shining bony gill-covers^ 

 which move freely, and leave a large opening on each side for 

 the gills. Each nostril has two apertures separated merely by 

 a thin membrane, which projects from the surface, and serves 

 as a valve for one or other. In a few of the smaller species, 

 I have not been able to trace this structure ; but, in the larger 

 species, it may be considered as existing, when the contrary is 

 not mentioned in the description. The membrane of the gill- 

 cover very generally contains three rays, and never more than 

 four. The former is to be supposed as the case wherever the 

 contrary is not mentioned. 



Kk 



