1913.] NATURAL SCIENCES OF PHILADELPHIA. 543 



process; snout 3j to 3f in head; eye 2f to 2f ; maxillary 2| to 2|; 

 interorbital 2| to 3; length 52 to 55 mm. 



This form seems to be closely related to Moenkhausia lepidura 

 (Kner). It perhaps approaches nearest the subspecies M. lepidura 

 gracilima Eigenmann, differing apparently only in color, so far as 

 the short account will permit of comparison. Villa Bella specimens 

 are described as having the color of the caudal faint, a duskiness ex- 

 tending upon lower caudal lobe, and humeral spot not well defined. 

 Serpa specimens have middle caudal rays and distal parts of other 

 rays, and upper and lower edges of fin, dusky. 



(Named for the Madeira River.) 

 Hemigrammus melanochrous sp. nov. Fig. 12. 



Head 3f; depth 3f; D. ii, 9; A. iv, 18, i; P. i, 10; V. i, 7; 

 scales 32 in median lateral series to caudal base, and 2 more on latter; 

 1. 1. of 7 tubes anteriorly from shoulder; 10 scales transversely 

 between dorsal and ventral origins; 10 predorsal scales to occipital 

 process; head width 2yV its length; head depth at occiput 1^; 

 snout 3f; eye2f; maxillary 2; interorbital 2| ; first branched dorsal 

 ray 1; first branched anal raj^ 1^; least depth of caudal peduncle 

 2f; pectoral IJ; ventral If. 



Body elongately ovoid, deepest at dorsal origin, compressed 

 profiles more or less similar, and edges all convexly rounded. Caudal 

 peduncle well compressed, and its least depth nearly equals its length. 



Head moderate, compressed, lower profile a little more inclined 

 or convex than upper, and nearly flattened sides slightly approxi- 

 mating below. Snout convex over surface and in profile, length 

 about f its width. Eye large, rounded, rather high, and its centre a 

 little anterior in head. Pupil large, rounded. Eyelids free, not 

 adipose-like. Mouth large, wide, commissure rather short. Lips 

 rather thin and mostly firm. Maxillary long, rather slender, well 

 inclined, free, and extends back opposite front pupil edge. Teeth in 

 upper jaw biserial, those in inner row larger, quindentate. No 

 maxillary teeth. Mandible with a row of ten quindentate, large, 

 subequal teeth, though no small posterior lateral ones. Inner buccal 

 folds broad. Tongue moderate, depressed, rounded and free in front. 

 Mandible strong, surface convex, rami of moderate and uniformly 

 low height inside mouth, not elevated, and when closed even with 

 snout tip. Suborbitals well developed, infraorbital almost covering 

 cheeks, but very narrow naked strip below, smooth. Hind edge of 

 preopercle vertical, smooth. Opercle deep, upper hind edge emar- 

 ginate. Occipital fontanel broad, extends from anterior interorbital 



