Mr. J. M'Clelland on Indian Cyprinidae. 41 



stagnant waters ; and in the Gonorhynchs for tearing and up- 

 rooting certain kinds of confervoid plants, which form a short 

 slimy covering to the rocks on which they grow in clear moun- 

 tain streams. 



6. The true Cyprins {Cyp.projjrius, Cuv.), together with the 

 Barbels, Cirrhins and Labes, subsist less exclusively on a ve- 

 getable regimen. Their mouths are invai'iably small, and 

 either directed downward or situated low in the head ; and as 

 far as my inquiries have extended, it is on such modifications 

 of the mouth that we find the length of the intestines and 

 the habits of the different groups to depend. 



7. In the Gudgeons the mouth is formed simply for re- 

 ceiving a kind of food that is obtained in abundance without 

 any eifort, and which requires no prehensile teeth or other 

 organs for its collection or preparation before it is submitted 

 at once to the process of digestion. The mouth is conse- 

 quently small, and is opened and closed chiefly by the mus- 

 cular structure of the snout ; the jaws are weak, and the lips 

 hard and cartilaginous, without sensibility or muscularity, and 

 their intestinal canal varies from eight to eleven, and even 

 twelve lengths of the body, including the head and caudal 

 fin: except in the Hypostomi, Lacep., among fishes. Ostrich 

 among birds, and perhaps some of the ruminants, such de- 

 velopment of the abdominal canal is rare, a circumstance 

 which it will be necessary afterwards to recollect when speak- 

 ing of types. 



8. In the Gonorhynchs the muscular power of the snout is 

 greater than in the Gudgeons ; the mouth is smaller, and si- 

 tuated further back in the lower surface of the head ; the lips 

 thicker, and though defended externally by a hard insensible 

 cartilage, are formed for very powerful muscular action. In 

 this genus the length of the intestinal canal is usually about 

 eight lengths of the body, and exceeds that of all other Cy- 

 prins except the Gudgeons. 



9. The development of the intestinal canal in Cyprinidce 

 differs with the habits of species, so as to afford something like 

 a basis for true distinctions between the different genera, and 

 is fortunately connected with such peculiarities of form and 

 colour as to render it easily available as a guide to an improved 

 method of classification. 



10. The philosophical views of Mr. MacLeay regarding 

 the circvdarity of groups, left it almost certain that the law 

 which applied to other classes might be also applied to fishes ; 

 and as the essence of that law consists in the tendency of the 

 contents of natural groups to form a circle, it became highly 

 probable, that as strictly herbivorous Carps were known, so, on 

 the contrary, carnivorous species might be expected also to 



