DISTRIBUTION OF INDIAN FRESHWATER FISHES. 561 



from this consideration whether at some earlier period of the 

 world's history a migration of fishes occurred from the north, 

 and as they travelled south some found their way into Africa, 

 others into India; while as their distance from their base increased, 

 and due to climatic and other disturbing causes, they became mo- 

 dified as we now find them. Although all the genera of fishes 

 which I have alluded to as common to Africa and India are fresh- 

 water, some are commonly residents within tidal influence. I 

 will therefore subdivide the 14 genera into (1) strictly freshwater 

 forms, and (2) those which contain some representatives which 

 reside in the sea. 



Genera. 



' Ethiopian 



Mediterraneo- 



subregion. 



Persic subregion. 



u 



( Mastacembelus 



W. Africa. 



Present. 



o 





All. 





C3 





AU. 





on 





E. Africa. 





1 • 





All. 









AU. 









E. Africa. 



Absent. 







E. Africa. 







W. Africa 1. 







( Perioplithalmus | 



E. & W. & •) 





- g ^ 





S. Africa. J 



>> 







AU. 



Present. 



=° Z-3 





E. 







^ Haplochilus 



E. 



Absent. 



It would thus appear that the irruption of the majority of the 

 freshwater forms common to Africa and India must have been by 

 way of the Mediterraneo-Persic subregion. 



We have now to consider what freshwater fishes are found 

 in the various subregions of the Oriental region, and which are 

 peculiar to each. I propose taking Mr. Wallace's subdivisions, 

 having the deltas of the Granges, Indus, and the Brahmaputra as the 

 boundaries of the Hindustan subregion on the N.W., N., and N.E., 

 while on the S.W. it extends to the Ceylonese subregion. The 

 Ceylonese subregion commences on the western coast below Goa, 

 and includes Canara and Malabar with the western G-hauts to 

 Ceylon ; passing along the Neilgherries, its fish fauna in Mysore 

 joins with that of the Hindustan subregion ; while in the Car- 

 natic it extends in like manner as high as the river Kistna. Out 



* This Malayan element in West Africa corresponds with what has been ob- 

 served in mammals and birds. 



LINN. JOURN. — ZOOLOQV, VOL. XIV. 41 



