46 MEMOIRS OF THE CARNEGIE MUSEUM. 



emarginate, its origin below some part of the last dorsal ray, its base greater than 

 length of head; origin of ventral below origin of dorsal, just reaching anal, or a 

 little shorter; pectorals short,. just about reaching ventrals. 



Scales thin, the margins convex, with many radial striae; lateral line but little 

 decurved; anal naked; caudal lobes scaled for one-fourth to one-third of their 

 length. 



A small, but conspicuous humeral spot, about equal to the size of the pupil, 

 over the fourth scale of the lateral line; middle caudal rays faintly peppered, or a 

 faint dusky streak parallel with the margin in the middle and the upper lobe of 

 the caudal, the rays beyond them dotted. 



Genus X. Leptobrycon^^ gen. nov. 



Type : Leptobrycon jatuaranoe Eigenmann. 



Very similar to Parecbasis. Anal short, the highest ray, the fourth, extending 

 beyond the tip of the last; lateral line short; mouth very large, the premaxillary 

 very feeble, the maxillary very large, the upper margin thickened; lower jaw 

 scoop-shaped, the sides raised; teeth numerous (fourteen in the premaxillary), 

 feeble, conical, none on the maxillary, or on the raised part of the mandible; cheeks 

 partly naked; postorbitals three, covering most of the postorbital area; no pseudo- 

 tympanum; both fontanels large; adipose well-developed. 



21. Leptobrycon jatuaranae Eigenmann sp. nov. (Plate VI, fig. 1.) 

 20952, M. C. Z., type, 29 mm. to base of caudal. Jatuarana. Navez. 

 Head 3.75; depth 3.5; D. 11; A. 14; scales ?. Eye 2.5 in the head con- 

 siderably larger than the interorbital; occipital reaching about one-sixth to the 

 dorsal; frontal fontanel much narrower than the parietal, its length about 1.25 

 in the length of the parietal; interorbital nearly flat; maxillary very large, slightly 

 longer than the eye, reaching to below the pupil, its front margin quite convex, its 

 proximal margin slightly concave and thickened; premaxillary altogether transverse, 

 each premaxillary with about fourteen minute, apparently conical teeth, without 

 lateral notches. Mandib!e with minute teeth on its anterior edge, the side of the 

 jaw upturned. Third suborbital narrowly in contact with the preopercle below. 

 A small naked angle below its anterior edge. A narrow naked strip behind it. 

 Gill-rakers 8 -1- 17, long and slender, the longest more than half length of eye. 



Origin of dorsal equidistant from tip of snout and base of caudal; origin of 

 anal behind the vertical from last dorsal ray; base of anal not much longer than eye, 



■'■ XeiTTos, small, or delicate; Drycon, a related genus of the Characidse, from /Spi/tw, to eat greedily. 



