242 



THE AMERICAN CHARACIDAE. 



bordered on the sides by 5 scales; skull smooth, very convex. Frontal fon- 

 tanel shorter than the parietal, extending to above the anterior margin of the 

 pupil. Margin of second suborbital very convex, leaving but a narrow naked 

 area. Maxillary 2.66 in the head. The mouth large. Four to six teeth in 

 the front row of the premaxillary, the third withdrawn from the line with the 

 rest; five teeth in the second series, their denticles in a straight line; eight large 

 teeth in the lower jaw (four on each side) arranged in a crescent; small teeth on 

 the side. 



Scales of the sides and back regularly imbricate, a few interpolated scales 

 over the anal muscles; a row of about 12 scales forming a sheath along the base 

 of the anterior anal rays. Scales of belly and breast not very regularly arranged; 

 lateral line but httle decurved; axillary scale well developed. 



Dorsal equidistant with the ventrals from the snout, its origin a Uttle 

 in advance of the middle, its highest ray 3i in the length. Anal emarginate. 

 Ventrals not reaching anal. Pectorals slightly beyond the origin of ventrals. 



Highly iridescent ; a round spot over the 7th-9th scales of the lateral line 

 with a dark streak extending down from it and another curving upward and 

 forward, surrounded by a light court; sides and fins thickly punctated especially 

 in a lateral band on a level with the humeral spot. Tip of first anal ray some- 

 times milk-white. 



10. AsTYANAX (PoECiLURiCHTHYs) zoNATus Eigeumann. 

 Plate 41, fig. 3. 



Astyanax zoiiatus Eigenmann, Bull. M. C. Z., 1908, 52, p. 95; Rept. Princeton univ. exped. Patagonia, 

 1910, 3, p. 432. 



Habitat. — Tabatinga. 



Specimens examined. 



Allied to A. anterior and A. asymmetricus; distinguishable from other 

 members of the genus by its cross-bar-like caudal spot. 



■ To base of caudal. 



