220 THE AMERICAN CHARACIDAE. 



Caudal spot absent. Humeral spot represented by the expansion of the 

 anterior end of a very distinct broad lateral stripe which is bordered above with 

 a silvery band. A crescent of silvery bordering the lower side of the humeral 

 expansion of the lateral stripe. The scales below the stripe slightly iridescent. 



36. Hyphessobrycon melanopleurxjs Ellis. 



Plate 30, fig. 4. 

 Hyphessobrycon melanopleura Ellis, Ann. Carnegie mus., 1911, 8, p. 157, pi. 3, fig. 2. 



Habitat. — Rio Tiet6 Basin. 



Specimens examined. 



Head 3.8; depth 3.2 to 3.5; D. 10 or 11; A. 26 to 28; scales 6 or 7-30 to 

 36-5; eye 3 in the head; interorbital a little greater than the eye, 2.5 in the 

 head. 



Compressed. Depth of head at the base of the occipital process 1.3 in the 

 greatest depth. Preventral and predorsal regions narrowly rounded, without 

 complete series of median scales. 



Occipital process short, about 8 in the distance from its base to the dorsal. 

 Interorbital nearly flat. Frontal fontanel narrowly triangular, as wide as the 

 parietal and 1.5 in the parietal without the occipital groove. Maxillary a little 

 less and mandible a little more than the eye. Mouth rather large; snout very 

 short, 1.8 in the head. Premaxillary with four tricuspid teeth in the inner 

 row, and two or three shghtly narrower teeth in the outer row. Maxillary with 

 four or five narrow tricuspid to conical teeth. Dentary with a series of four 

 strong tricuspid teeth, followed by about seven minute conical ones on the side. 



Gill-rakers 6+9, each with a single row of very small spines. 



Lateral line with pores developed on 7 to 9 scales. 



Origin of the dorsal nearly the length of the eye nearer the caudal than to 

 the snout; highest dorsal ray 1.3 in the head. Origin of the anal on the vertical 

 from the third dorsal ray. Anal rather deeply emarginate; longest anal ray 

 about 2 in the base of anal and about 1.7 in the head. Ventrals on the vertical 

 from the fourth or fifth scale in front of the dorsal. Ventrals short and weak, 



