86 THE AMERICAN CHARACIDAE. 



in the type forming a network in the median scales. In others they are more 

 regular, rarely anastomosing but those from above and below meeting along 

 the median line. 



Head 3.5^1; depth usually 2 in the adult (2.4 in some of the specimens 

 from Obidos and in the young). D. 10 or 11; A. usually 26-28 1 ; scales 5-31 

 to 34 2 -4. Eye 2.33-2.5 in the head; interorbital equals eye, or but a trace larger. 



Compressed, oval, without notable breaks in the nearly symmetrical curves; 

 profile scarcely depressed over the eyes, ventral profile slightly more arched than 

 the dorsal; pre ventral area with a median series of about twelve flat scales 

 bordered on the sides by series of angularly bent scales; postventral area with 

 a median series of moderate sized thin scales, bent and bordered on the sides 

 with a series of symmetrical or nearly symmetrical scales, the area compressed; 

 predorsal region narrowly rounded, the median series of about nine scales extend- 

 ing from dorsal to occipital crest. 



Occipital process one fourth to one fifth in the distance from its base to 

 the dorsal, bordered on the sides by three scales; interorbital very slightly con- 

 vex; second suborbital leaving but very narrow naked border; maxillary not 

 reaching to end of second suborbital, equal to the distance from tip of snout to 

 pupil ; four or five, rarely six, in one case seven, teeth in the front series of the 

 premaxillary forming a continuous series on each side; the third tooth slightly 

 behind the line of the others; five graduated teeth in the second row; four large 

 teeth in the mandible, slightly graduated; minute teeth on the sides of the 

 lower jaw, maxillary with one or two teeth. 



Gill-rakers about 9 + 12. 



Scales deeply imbricate with one to two pairs of widely divergent striae 

 exposed and several pairs concealed; anal sheath consisting of one to three 

 rows of minute scales in front and a single row behind, more or less sharply 

 marked off from the scales of the sides; lateral line scarcely bent up in front, 

 a well-developed axillary scale; caudal lobes densely scaled to near their tip. 



Origin of dorsal a little in advance of middle. Its first divided ray two and 

 a half times as long as the last, three and a half in the length; anal emargi- 

 nate, the first rays at least twice the length of some of the posterior ones; origin 

 of ventrals about equidistant from tip of snout and tip of last anal ray, equi- 

 distant from tip of snout with the dorsal; ventrals scarcely reaching anal in 



1 In thirty specimens from the Amazon Basin one has twenty-four, one twenty-five, seven twenty-six, 

 ten twenty-seven, five twenty-eight, two twenty-nine, two thirty, and two thirty-two anal rays. 



2 Of nineteen specimens from the Amazon Basin, three have thirty-one, five thirty-two, eight thirty- 

 three, and three thirty-four scales with pores, 



