Family XL Poeciliid^. 



147 



sides, but has neither the black caudal spot nor the crescent; the fourth 

 black bar on left side is bifurcate in its lower half; dorsal fin with a 

 black band across its middle and another at the tips ; tips of anal rays 

 black; ventrals and pectorals plain. 



137. Platypoecilus nelsoni sp. nov. 



Type, No. 51484, U. S. National Museum, 1% inches in length; 



Papayo, Guerrero. 

 Basin of the Rio Balsas. 





m 



Fig. 46. Platypcecilus nelsoni Meek. 



Head 3§; depth 3,1; D. 7; A. 6; scales 10-28. Body elongate, 

 moderately compressed; head large, snout pointed, 3^2 in head; inter- 

 orbital slightly convex, 2 in head; mouth small; teeth close set, conical, 

 their tips bent slightly backward; diameter of eye 3^; origin of the 

 dorsal fin midway between base of caudal and posterior margin of the 

 opercle ; pectoral 1 % in the head ; ventrals 2 ; caudal fin rounded ; least 

 depth of caudal peduncle i-| in head; no lateral line, many of the 

 scales with pore-like depressions in their centers. 



Color olivaceous, with a few faint vertical bars on posterior half of 

 body; center of each scale lighter, the margins making faint longitu- 

 dinal stripes along rows of scales. One specimen has two ink-like spots 

 at base of caudal; a second specimen has only the upper one, the other 

 two have none. Longest specimen 1.86 inches. 



The only specimens of this species known were collected by E. 

 W. Nelson at Papayo, Guerrero, on April 20, 1903, and were kindly 

 loaned to the Museum by Dr. B. W. Evermann. 



GO. Heterandria Agassiz. 



Heterandria Agassiz, Amer. Jour. Sci. & Arts, 1853, 135 {Limia 



r ormosus Girard). 

 Body rather slender; mouth very small; the lower jaw short, its 

 bones not united ; snout short ; both jaws with a single series of slender, 



