166 THE AMERICAN CHARACIDAE. 
Head 3.6 to 4; depth 2.8 to 3.5; D.11; A. 19 to 22; scales 5-31 to 34-3; 
eye 2.25 in the head; interorbital about equal to the eye, 2.3. 
Compressed; depth of head at the base of the occipital process about 
1.66 in the greatest depth. Dorsal profile only slightly arched. Preventral 
region rounded, without a complete series of median scales. Predorsal region 
rounded, often with a complete series of 9 to 11 median scales. 
Occipital process 5 in the distance from its base to the dorsal. Inter- 
orbital very slightly convex. Frontal fontanel triangular, as wide as the parietal, 
three fourths the parietal without the occipital groove. Second suborbital 
narrow, leaving a narrow naked margin behind and below. Snout short, 
mouth very small. Lower jaw scarcely projecting beyond upper, even when 
the mouth is open. Maxillary convex in front, little more than half the eye, 
3.5 in the head. Mandible equal to the eye. Premaxillary with two or three, 
5-pointed teeth in the outer row, and four or five 5- to 7-pointed teeth in the 
inner row. Maxillary with two or three 4- to 7-pointed ‘teeth. Dentary with 
five broad, 5- to 7-pointed teeth, followed by a series of several small teeth on 
the sides. 
Gill-rakers 6 + 7. 
Caudal sealed over the basal half. Anal sheath short, of about 3 scales, 
covering the base of first 5 or 6 rays. Pores developed on the first 7 to 9 scales 
of the lateral line. 
Origin of the dorsal equidistant from the snout and caudal, penultimate 
ray two fifths of the longest, which is 3.25 in the length. Caudal about one 
third the length of the eye longer than the head. Origin of the anal on the 
vertical from the second scale behind the dorsal. Anal almost faleate, the long- 
est ray about 1.2 in the length of the anal base. Ventrals on the vertical from 
the first dorsal rays or the first scale in front of the dorsal. Ventrals just reach- 
ing the anal. Pectorals reaching the first scale in front of the ventrals. 
No caudal spot, humeral spot small and round, usually faint and often 
lacking. A narrow, blackish, lateral stripe overlaid with silvery, from the base 
of the caudal to the humeral spot, if the humeral spot is present. Fins all 
hyaline. Seales of the back outlined with dusky. Bluish and greenish iri- 
descence on the sides and cheeks. 
