CYPKIXIDJ3. CTPEININJE. 239 



The size of scales cannot by itself be depended upon for dis- 

 tinguishing genera, because large, moderate, and small-sized scales 

 are all occasionally found represented in a single genus. But 

 certain modifications may exist, as in the mountain barbels, ScJiizo- 

 ihorax and its allies, where a row of tile-like scales encloses the 

 excretory outlets and the base of the anal fin ; or portions of the 

 body may be naturally left scaleless. 



The pharyngeal teeth are in from one to three series, but 

 these numbers alone do not always suffice for the definition even 

 of genera : thus in Chela some species have teeth in two and 

 others in three rows. Even the form of the teeth is not invariably 

 similar in all the species of the same genus : thus in the Kohtee 

 microlepis, Blyth, the teeth have serrations on their edges, and the 

 two largest of the anterior row are molariform, whereas crooked 

 and pointed teeth are the rule in the genus. Likewise the teeth 

 are deciduous, being constantly shed and replaced ; they may be- 

 come blunted with age, although they had at first been sharp and 

 pointed. 



I have not retained the subfamily Homalopterince, or carps des- 

 titute of an air-bladder, because Psilorhynclius links it very naturally 

 with Discognathus. The principal distinctive characters consist of 

 the single row of pharyngeal teeth and the absence of the air- 

 bladder. In many families these are deemed insufficient even to 

 characterize genera. Homaloptera leads very naturally from some 

 of the mountain siluroids to the true carps on the one hand, and to 

 the loaches on the other. 



Bleeker observed that the subfamily of ffomalopterince is well dis- 

 tinguished from other cyprinoids by the central position of the 

 mouth on the lower surface of the head, and the character of the 

 pectoral ray. 



Synopsis of Indian Genera. 



A. Abdomen rounded, not cutting. 



a. Dorsal fin 'commencing nearly opposite 



the ventrals. And short (5 to 7 



branched rays). 

 Anterior portion of body depressed; 



snout .spatulate ; mouth on lower sur- 

 face of head ; 6 barbels. Pharyngeal 



teeth in one row. Outer pectoral rays 



unbranched or simply bifurcated. 



Scales small 1. HOMALOPTERA. 



Anterior portion of body somewhat de- 

 pressed; snout rather spatulate. Mouth 



inferior ; no barbels. Outer pectoral 



rays unbranched. Scales of moderate 



size 2. PSILOEHYNCHUS. 



Mouth inferior, with a suctorial disk on 



the chin ; 4 barbels. Pharyngeal teeth 



in 3 rows. Scales of moderate size. 



Pectoral fins subhorizontal 3. DISCOGNATHUS. 



