1913.] NATURAL SCIENCES OF PHILADELPHIA. 561 



inserted little before dorsal. Caudal well forked. Pectorals large, 

 falcate, reach back well beyond dorsal base. Ventrals small. No 

 humeral blotch. Caudal with black blotch. 



Small fishes of the Amazon basin. They are remarkable for the 

 simple dentition, in this respect differing from the rest of the members 

 of this subfamily. They also suggest certain Characince, as Asiphon- 

 ichthys, though differ in the larger pectorals and conic teeth. Pos- 

 sibly they are more closely allied with Pseudocorynopoma of the 

 present subfamily, but differ in the incomplete lateral line, as well 

 as the dentition. 



(/Vacyoc, jaw; Xafia':^ Cliarax; with reference to the long maxillary.) 

 Gnathocharax steindachneri sp. nov. Fig. 19. 



Head 3|; depth 3i; D. ii, 6, i; A. iii, 31, i; P. i, 15; V. i, 7; 

 scales 33 in median lateral series to caudal base and 2 more on latter ; 

 10 scales transversely between dorsal origin and that of anal; 14 

 predorsal scales; head width 1| in its length; head depth at occiput 

 1^-; mandible 1^; first branched dorsal ray 1^; first branched anal 

 ray \\; least depth of caudal peduncle 3^; ventral 2; snout 4| 

 in head measured from upper jaw tip; eye 2\; maxillary 1^; inter- 

 orbital 3|. 



Body elongate, greatly compressed, deepest at dorsal origin, upper 

 predorsal profile nearly straight and little inclined, and lower anterior 

 profile well curved convexly. Upper edges convex, preventral 

 largely convex with slight median keel and postventral constricted. 

 Caudal peduncle well compressed, about long as deep. 



Head moderate, well compressed, upper profile straight and little 

 inclined, lower profile well inclined convexly, and rather convex 

 sides slope evenly above and below. Snout short, near/y straight 

 in profile, convex over surface, and length about half its width. Eye 

 large, rounded, little elevated, and centre slightly anterior to middle 

 in head length. Pupil moderatelj^ large, rounded. Eyelids free, 

 not adipose-like. Mouth large, superiorly terminal. Maxillary very 

 long, slender, slips below preorbital edge most of its length, extends 

 down below eye till opposite last | in eye diameter, and. its greatest 

 expan'^ion about 5 in eye. Lips thin, firm, little developed. Teeth 

 uniserial in jaws, conic, somewhat irregular, sharply pointed, and 

 rather short. Mandible with 3 pairs of wide-set canines anteriorly. 

 No maxillary or palatine teeth. Inner buccal folds moderate. 

 Tongue rather small, depressed, a little elongate, nearly truncate, 

 and free in front. Mandible slightly protrudes when closing, strong, 

 rather shallow with convex surface and rami not elevated inside 



