INDIAN CYPRINID^. 



249 



bladder, while in the only species of the latter which I have been able 

 to inspect I found that organ, though small and peculiar in its form, yet 

 sufficiently developed to lessen considerably the specific gravity, enabling the 

 SchisturcB to swim with facility, though perhaps with less buoyancy and 

 ease than other Cyj)rinidcB.'^' But if a natatory bladder exists at all in the 

 true Loaches ( Cobitis prop.) or those whose caudal is entire, it must be in the 

 manner described by Schneider — very small and enclosed in a bony bilobate 

 case which adheres to the third and fourth vertebrge, but even in this 

 rudimental shape I have been unable to find an air vessel in any Indian 

 species yet examined.f 



This peculiarity, together with their small and weak fins, as well as 

 lengthened and cylindric form, approaching to that of the 3IurcEnidcs, 

 afford satisfactory evidence that they are less adapted for swimming than 

 any other Cypr 'inidce, and may therefore be said to be more terrestrial in 

 their habits, living chiefly on sandy and muddy bottoms, or in jeels amidst 

 aquatic vegetation. 



* Schistura dario and geta have a membranous air vessel placed in the upper part of the 

 abdomen as in ordinary Cyprins, but it consists only of a single lobe. S. dario, Buch. is the 

 only species of the Linnsean genus which I have found to frequent deep waters in the open channels 

 of the Ganges and Braraaputra. 



t Since this was written, I have found the air vessel in all these species situated in a small bony 

 case immediately over the entrance of the oesophagus from the mouth. Plate 56. f. 5, is a magnified 

 representation of the organ (which is not larger than the head of a pfn) as it occurs in Cobitis 

 guntea, Buch. and other neighbouring species of the same sub-genus. Fig. 4, Plate 56, represents the 

 same organ in several of the smaller Schistune, in which it is also placed over the entrance of the 

 wsophagus, and in both cases probably answers the purpose of the branchial or pharyngeal teeth in 

 the Pceonomince, especially as the external surface of the bony crust which surrounds the air- 

 vessel is, as represented in tlic figures, studded witii niiiuito spines. 



K 



