THE AMERICAN TETRAGONOPTERINAE. 101 



rays and anal lobe less intensely yellow or orange. The black of the caudal is 

 most variable, darkest near the orange spot or nearer the tip, the part of one 

 color shading gradually into that of the other or with an abrupt broken divid- 

 ing line or "water marked." 



Vertebrate 14+17. 



Posterior air-bladder of nearly equal width throughout, its width equal to 

 the diameter of the eye, its length nearly twice that of the anterior section; ali- 

 mentary canal not quite equal to the entire length. 



22. Moenkhausia lepidura lata Eigenmann. 

 Plate 101, fig. 10. 



Moenkhausia lepidurus lotus Eigenmann, Bull. M. C. Z., 1908, 52, p. 103 (Rio Tapajos); Rept. Prince- 

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



20860 Cotypes 27 55-75 mm. Rio Tapajos. Dexter, James, and Talisman. 



These specimens differ from others from the Tapajos and from various other 

 localities. The anal rays average 26 + ; five specimens have twenty-five, 

 eleven twenty-six, eight twenty-seven, and four twenty-eight rays. The body 

 is deeper, the depth averaging 2.6 of the length; the scales in the lateral line 

 vary from 32 to 34, being most frequently 33. 



The middle caudal rays are but faintly colored if at all, but the upper caudal 

 lobe is black. 



23. Moenkhausia lepidura icae Eigenmann. 

 Plate 101, fig. 6. 



Moenkhausia lepidurus icae Eigenmann, Bull. M. C. Z., 1908, 62, p. 103 (Iga); Rept. Princeton univ. 

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



Habitat. — lea. 



20810, 20812 Cotypes 46 30-50 mm. Ica James 



Deep, compressed fishes, depth three in the length; anal rays usually 

 twenty-three or twenty-four; two have twenty-one, six twenty-two, ten twenty- 

 three, thirteen twenty-four, and one has twenty-five rays; the scales in the 



