11)14. J NATURAL SCIENCES OF PHILADELPHIA. 239 



examples all agree with the type in the constancy of their color 

 patterns. 



The present species is distinguished from its ally, the preceding, 

 by the presence of an extra black streak before the dorsal. 



(Para, near; aUernus, alternate, the related species.) 



MYOCHARAX subgen. nov. 

 Type Leporinus desmotes sp. nov. 



Differs from the subgenus Anostomus in the dentition, that of the 

 mandible being composed of two^ long slender curved rodent-like 

 incisors, and also two somewhat similar though much shorter ones 

 externally and well back. Upper jaw with six tricuspid incisor-like 

 teeth. Anterior nostrils in rather long cutaneous tubes. 



One species, described below. 



{Mu?^ mouse; x"-pf^^, Charax; with reference to the rodent-like 

 teeth.) 



Leporinus desmotes sp. nov. Fig. 5. 



Head 4; depth 4f ; D. iii, 10, i; A. iii, 8, i; P. i, 16; V. i, 9; 

 scales 35 in lateral line to caudal base and 6 more on latter; 6 scales 

 .above 1. 1.; 5 scales below 1. 1. to ventral origin; 5 scales below 1. 1. 

 to anal origin; 13 predorsal scales; head width 2 in its length; 

 head depth at occiput IJ; snout 2|; eye 4; maxillary 4; inter- 

 orbital 2\; first branched dorsal ray 1; first branched anal ray 1|; 

 least depth of caudal peduncle 2f ; upper caudal lobe 1|?; pectoral 

 If; ventral 1^. 



Body elongate, compressed, tapers somewhat posteriorly, deepest 

 at dorsal origin, anterior upper profile rather evenly convex, and 

 edges all convexly rounded. Caudal peduncle compressed, about 

 long as deep. 



Head rather small, compressed, somewhat conic, surfaces rather 

 conic, and profiles similarly straight and inclined. Snout conic, 

 broad, length | its width, and as seen from above rather acuminate. 

 Eye rounded, lateral, and centre falls trifle behind middle in head 

 length. Adipose-eyelid narrow, best developed anteriorly. Mouth 

 small, inferiorly terminal. Maxillary with thick integument, well 

 inclined and reaches trifle over half way to eye or about opposite 

 front edge of posterior nostril. Lips thick and fleshy. Upper lip 

 broader, with two series of fleshy lamellae, of which outer show 

 much deeper clefts, are longer, though more vaguely defined exter- 

 nally. Lower lip peculiar, with deep-cleft narrow fleshy lobe each 

 .side leaving broad symphyseal surface, this crowTied with seven or 



