THE AMERICAN TETRAGONOPTERINAE. 



97 



the vertical from the last dorsal ray; ventrals not reaching anal, pectorals to 

 ventrals. 



A well-defined, silvery, lateral band, half as wide as the eye along the middle 

 of the sides, tapering from below the dorsal forward; middle caudal rays black, 

 caudal lobes beyond the tips of the middle rays black, the tips milk-white. The 

 intensity of the caudal color differs very much with the condition of the speci- 

 mens, the method of preservation, and the locality; an insignificant humeral 

 spot not evident in alcoholic specimens. 



The silvery lateral band of the sides is underlaid with a black band of the 

 same size and shape. In formaline specimens in which the silvery band is 

 dissolved a black band takes its place. Base of caudal lobes in life bright yellow, 

 dorsal and adipose yellowish. 



Vertebrae 13 + 18. 



Posterior air-bladder sausage-shaped, its diameter about equal to that of 

 eye, its length twice that of the anterior section, bent down somewhat to near 

 the origin of the anal. 



Alimentary canal less than the total length with the caudal. 



20. Moenkhausia intermedia Eigenmann. 

 Plate 16, fig. 2; Plate 101, fig. 8, 9. 



Moenkhausia dichrourus intermedins Eigenmann, Bull. M. C. Z., 1908, 62, p. 103 (Tabatinga); Rept. 



Princeton univ. exped. Patagonia, 1910, 3, p. 438. 

 Moenkhausia lepidura madeirae Fowler, Proc. Acad. nat. sci. Phila., 1913, p. 540, fig. 11 (Tributary of 



Rio Madeira near Porto Velho). 



Habitat. — Amazon, Paraguay, and Parana Basins. 



Specimens examined. 



Catalogue Number of Length 

 number specimens in mm. 



20762 Cotypes 2 



3709 C. 4 



3700 C. 1 



3702 C. 2 



Locality Collector 



42-64 Tabatinga Bourget 



25-43 San Louiz de Caceres Haseman 



47 Rio Santa Rita, near frontier of Bolivia Haseman 



60-67 Salto Avanhandava Haseman 



Closely resembling M. dichroura from which it differs mostly in the shape 

 of the open mouth. 



