ON ICHTHYOLOGY IN GENERAL. 
7 
fresli-water fishes of the Indian Peninsular is the 
geographical distribution of species and groups. 
India affords a splendid example of a well defined 
region. The great range of the Himalaya cuts it 
off most completely from the rest of Asia, and the 
sea being the boundary on almost every other side, 
it is manifest that no fresh-water species, as such, can 
at the present time have communication with other 
countries. Hence very few truly fresh-water species 
that are found in India occur in other countries ; a 
few only extend to Burmah and the Malay Archipe- 
lago on the one side, or to Afghanistan on the other ; 
one species, frequenting mountain streams, is found 
as far west as Syria. This subject will be further 
discussed when describing the Genera and Species in 
detail. 
