THE AMERICAN TETRAGONOPTERINAE. 



301 



in the Upper Atrato, 3G-37 (rarely 40) at Soplaviento and 39 to 41 in the Upper 

 Cauca. 



Specimens examined. 



I have also had access to the specimens recorded by Meek and Hildebrand 

 in their Fishes of Panama. They came fromRios Capeti, Cupe, Grande, Yape, 

 Axuza, and Tuyra all of the Tuyra Basin; from Rios Calobre, Mamore, El 

 Capitan, Juan Diaz Abaco, and Marte Arnade. 



I shall fu'st describe typical specimens coming from the Rio San Francisco 

 and the Parana Basin, calling attention to the local deviations later. 



Head about 4.3; depth 2.6-3; D. 11; A. 25-34; ^ scales 7-34 to 41--6 to 7; 

 eye 2.5-3; interorbital slightly wider than the eye in the adult. 



Nearly symmetrically elliptical, without humps or depressions; preventral 

 area rounded, without a distinct median series of scales; postventral area nar- 

 rowly keeled; predorsal area narrowly keeled or rounded, with a series of about 

 12 nearly regular median scales. 



Occipital process i of the distance of its base from the dorsal, bordered by 



' See tables for details. 



^ 46 scales in a specimen from Cudajas. 



