Gonorhynchus. INDIAN CYPRINID^. 367 



in small scattered glands throughout the folds of the intestines, which usually 

 float in a copious oily secretion. 



The Cape species, G. vulgaris, Gm. the only one hitherto known, has 

 elongated opercula and branchial membranes ; still, from the description given 

 of it by authors, I conceive our Indian species to belong to the same group, 

 although they have short branchial apertures and rays, and are capable of 

 sustaining life for a considerable time out of water. Those I have exa- 

 mined are without a tongue, and the os. hyoides enters into the formation 

 of the lower jaw, being prolonged in front between its two lateral limbs 

 which are placed parallel to each other, and united anteriorly by dense fibrous 

 ligaments; these limbs are short, and articulated behind so as to admit of 

 very limited motion in the jaw, which thus resembles a valve, bounded in 

 front by the long projecting snout. 



The manner of feeding, for which this structure is intended, has been 

 described in detail in an account of one of the most characteristic species, G. 

 petropliilus, J. M. an inhabitant of high alpine streams.* This species subsists 

 on a slimy vegetable production derived from the surface of rocks and stones 

 in clear mountain torrents by swimming with sufficient force over the surface 

 on which the substance grows to uproot it by means of the depressed lower 

 jaw, which is formed for this purpose alone. 



It is not yet determined whether all the species have the same habits, as 

 they have not been watched with sufficient care ; but as they are always found 

 in clear mountain streams on rocky bottoms, or in the larger rivers along the 

 skirts of mountains, it is probable they all agree more or less in their mode of 

 procuring food. 



In the extraordinary length of their abdominal canal, they are only, if at 

 all, surpassed by the Gudgeons, and the entire tube is filled Avith a green 

 slimy substance, consisting no doubt of confervoid plants. 



* Jour. As. Soc. Bcng. Vol. iv, p. 39. wliore it is named Kemaon trout. 



