﻿ElGENMANN FlSHES OF WESTERN COLOMBIA 



9 



San Juan, or their furthest south in the Atrato, very probably 

 arose in the San Juan or south in the one case, or in the Atrato 

 and north (which in this case includes the Magdalena), in the 

 other. 



Attention should be drawn to a few instances of especial 

 interest. 



Astyanax fasciatus is overabundant in the Atrato. A few spe- 

 cimens were taken in the San Juan basin near the Atrato basin, 

 and it is quite possible that they have but very recently gone over 

 to the San Juan. (See above, p. 4, lines 9 to 12.) 



Of greatest interest is the distribution of Hoplias malabaricus, 

 and incidentally, of H. microlepis. The former is universally 

 distributed from the Atrato to Buenos Aires. It got from the 

 Atrato into the Tuyra, and into the San Juan and even into the 

 Patia. But both to the north of the Tuyra, in the Mamoni and 

 Chagres, and to the south of the Patia it is replaced by Hoplias 

 microlepis, a closely allied species. Has H. microlepis evolved 

 independently in the Chagres and the Guayas or has it been 

 crowded out between the two rivers by H. malabaricus? 



Of the species found both east and west of the Andes of Bogota, 

 only Astyanax fasciatus, Gymnotus carapo, Stemopygus mac- 

 rurus, and Hoplias malabaricus. are found in the San Juan. 



