8 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 99 



western, southern, and southeastern sides of the Maracaibo Basin, 

 stream capture has played some part in causing crossover of species 

 among the Orinoco, Magdalena, Catatumbo, Santa Ana, and Chama 

 Rivers. Just how extensive this may be must await extensive col- 

 lecting in the headwaters of those rivers. In general, the genera 

 occurring in the headwaters have a much more extensive distribution 

 than those in the lower courses and in the lowlands. All the following 

 genera of the Maracaibo Basin occur in the lower courses of the rivers 

 and are distinctive for that Basin and so far have not been found 

 outside of it: Sovichthys, Perrunichthys, Hoplomyzon, Tridensimilis, 

 Doraops, Saccoderma, Creagrutops, and Hubbsichthys. In a recent 

 letter Cecil Miles reports finding Dupouichthys in the Magdalena 

 system. 



In view of the fresh-water nature of the southern part of Lago de 

 Maracaibo, the fauna of all the rivers tributary to this lake may be 

 expected to have the same species, with some distinctive ones isolated 

 or restricted to the rapid or torrential parts of the rivers. This 

 appears to be true so far as my collections from this Basin are con- 

 cerned, but as yet no good collections have come from the headwaters 

 of the Catatumbo, Escalante, or Santa Ana Rivers, among others. 

 Undoubtedl}^ the number of species \^dll be nearly doubled when the 

 Basin including the lake itself, is thoroughly searched and studied. 



The numerous coastal streams emptying into the Caribbean Sea 

 along the north coast of Venezuela are almost unexplored ichthy- 

 ologically. "When studied they should present another interesting 

 chapter in Venezuelan ichthyology. These streams should be rich 

 in cyprinodonts and other genera and species of the lowlands. 



The fish fauna of the Valencia Basin is strikingly like that of the 



Rio Gudrico, with which it was once connected, but as in most of the 



stream systems it contains distinctive species not yet reported from 



elsewhere. 



DISTRIBUTION OF MARINE FISHES 



The specimens of fishes forming the basis of this report indicate in 

 general that the marine fishes of Venezuela form a part of that fauna 

 which extends from the Gulf of Mexico, Caribbean Sea, and West 

 Indies southward along the coast of Brazil to the mouth of the Rio La 

 Plata. Certain elements of that fauna, as far as is known at present, 

 appear to be restricted to such bodies of water as the Caribbean Sea, 

 Gulf of Venezucla-Lago de Maracaibo, and Gulf of Paria. Un- 

 doubtedly as further collecting is done the ranges of these and many 

 other species will be greatly extended. 



Lago de Maracaibo is a great body of water, brackish at its northern 

 end, probably salty in its deeper parts, but at least the great southern 

 end with its many canos is fresh at the surface. This condition has 

 made possible the infiltration of marine fishes from the Gulf of 



