Gobio. INDIAN CYPRINID&. 365 
salt-water. They are all used asa wholesome food by the people of India ; 
few of them however attain any very great size, or are much esteemed for 
their flavour by the wealthy. There is reason, I must observe, to believe 
that the quality of their flesh varies occasionally according to the ponds from 
which they are taken. 
As they do not prey upon each other, the size of the water into which 
they are introduced is the only limit to the extent to which they will propa- 
gate, provided merely that the S7/wride and similar carnivorous kinds be not 
allowed to flourish in the same ponds. If the proprietors of tanks were only 
to allow their fishermen to take the destructive kinds from their ponds for a 
season or two, such as the various kinds of Magur, Pabda, Singhi, Boalis, 
Aoar, Sal, &c. they would then find the Mrigala and other Bangons so 
numerous, as to repay the little attention required to prevent their destruc- 
tion. In Bengal fishes are so abundant that perhaps any great augmentation 
of their numbers is little to be desired ; but in the North-western Provinces 
the case is very different, especially where there are few tanks and streams ; 
and these I have found to be almost entirely abandoned to Pikes and other 
rapacious species, such as cannot allow the more profitable kinds to multiply, 
where, from a scarcity of water they ought to be preserved with the greatest 
care. When fishes are too much crowded in ponds, they are liable to 
epidemics. In June last, Mr. James Prinsep sent to me a number of Bangons 
from a pond at the Mint, in which they had become blind, some of one, and 
others of both eyes. Mr. Prinsep insisted on investigation of the subject, 
and with the aid of our friend Mr. J. W. Grant, we found the disease to be a 
dropsical affection of the membranes of the eye, by which an excess of fluid 
was secreted so as to cause that organ to protrude beyond the orbits, in some 
cases almost to the size of an egg. The fishes thus affected were all of tlie 
same species, Gobio limnophilus, and all in the pond were observed to be 
seized in the same way. The cause of this singular disease was of course less 
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