224 INDIAN CYPRINIDZ. 
substances, such as are found in stagnant waters, and in the Gonorhynchs 
for tearing and uprooting certain kinds of confervoid plants, which form 
a short slimy covering to the rocks on which they grow in clear mountain 
streams. 
6. The true Cyprins (Cyp. proprius Cuv.) together with the Barbels, 
Cirrhins, and Labes, subsist less exclusively on a vegetable regimen. Their 
mouths are invariably 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 receiving a 
kind of food that is obtained in abundance without any effort, 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 consequently small, and is opened and closed chiefly by the muscular 
structure of the snout; the jaws are weak, and the lips hard and cartilagi- 
nous, 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 development of the abdominal 
canal is rare, a circumstance Which it will be necessary afterwards to recollect 
when speaking of types. 
8. In the Gonorhynchs the muscular power of the snout is greater 
than in the Gudgeons ; the mouth is smaller and situated farther 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 intestinal canal is usually about eight lengths of the 
body, and exceeds that of all other Cyprins except the Gudgeons. 
