114 



Bulletin American Museum,' of Natural History. [Vol. XXXVI, 



Even within the restricted limits of the Colombian-Pacific Fauna and 

 under the uniform conditions which prevail in it, considerable racial varia- 

 tion has occurred. Note, for example, the distribution of the Capito- 

 squamatus-niaculicoronatus group as mapped herewith. Forms froni the 

 Atrato River not infrequently differ more or less from those from the San 



Fig. 8. Ranges of Capito squamaius and C. maculicoronaius — to illustrate the breaking up 

 of a characteristic Colombian-Pacific Fauna group into a distinct species south of the Fatia River and 

 three races north of it. 



1. Capito squamaius. 2, Capito maculicoronaius rubrilateralis. 



3. Capito maculicoronaius pirrensis. 4. Capito maculicororuilus mdculicoronutus. 



Juan River and southward, and others living south of the Patia differ from 

 those found north. This river indeed appears to form the northern limit 

 of a number of species, but in view of the lack of knowledge of the coast 

 region lying between the Patia and Buenaventura, it is not well to be 

 positive in this connection. 



