DISTRIBUTION OF INDIAN FRESHWATER FISHES. 575 



species, while Laheo, with its 25 species, is simply a Cirrhinayfiith. 

 more developed lips and a more extended dorsal fin ; and the 

 Burman forms of OsteocTiilus and Dangila are not very distantly 

 removed from CirrJiina and Laheo. 



Of the genus Barhus we have 3 subgenera : — (1) Barhodes, with 

 four barbels, the species of which, if soberly coloured, attain to a 

 large size, as the Mahseer to 90 lb., or even upwards of 100 lb., 

 in weight ; whereas those which are found richly coloured in 

 clear and rapid mountain-streams are usually small : a strong 

 dorsal spine (unless serrated) is mostly a sign that the species 

 exists in the vicinity of high mountains. (2) Subgenus Gapoeta, 

 with two barbels, never attain the size reached by many of those 

 with four barbels ; some, especially when residents of hill-streams, 

 are vividly coloured. (3) Subgenus Puntius, destitute of barbels, 

 are usually of a small size. 



If we briefly examine into the distribution of these three sub- 

 genera of the genus Barhus, we observe that the forms which 

 exist in the European subregion are only those possessing four 

 barbels ; that they are distributed as far as the other divisions of 

 the genus, but diminish in size the nearer they are to the tropics, 

 provided they are solely residents of the waters of the plains. 

 The subgenus Gapoeta has not been recorded from Europe, but 

 has been taken in Africa and also in Persia ; still its numbers are 

 small until we arrive at the Oriental region, throughout which 

 it is distributed. The subgenus Puntius appears to be confined 

 to Southern Africa and the Oriental region. 



The foregoing seems to show that the larger forms, all of which 

 are Barhodes, are probably descendants from Palsearctic progeni- 

 tors. And this view is still further confirmed if we investigate 

 where these fishes hreed. If the hot plains of India in which they 

 abound were the home of their ancestral forms from immemorial 



occurs not only in old examples of Discognathtis, but in other Carps having 

 Palsearctic representatives. I allude to a deep transverse fissure (generally 

 accompanied with numerous large glands in its vicinity) which in some adults 

 extends across the snout (see ' Fishes of India,' pis. 122 and 123), in others only 

 a trace of such is present. We see the same modification occur in large examples 

 of Laheo or Cirrhina in hilly regions and Assam, also, but to a less extent, in 

 some species of Barbus, as B. Thomassi from the western Ghauts and B. spi- 

 lophilos in Assam ; while the only other true Carp which has Palcsarctic repre- 

 sentatives (excluding ScapModon) is the Barilius, and in bill examples of 

 B. iileo this fissure is more or less well marked. 



