150 THE AMERICAN CHARACIDAE. 
Middle caudal rays with a round black spot; all other fins unmarked. A 
slate-black lateral stripe beginning on the vertical of the adipose fin and gradu- 
ally fading out again just below the origin of the dorsal. A silvery stripe on the 
scales below the lateral stripe. All of the scales below and half of the row just 
above the lateral stripe more or less covered with greenish golden iridescence 
that partakes of a turquois tinge as it approaches the anal, especially in speci- 
mens from Lago do Maximo and Lake Jose Assu, Brazil.’ 
9. HEMIGRAMMUS MICROPTERUS Meek. 
Plate 18, fig. 3; Plate 78, fig. 6. 
Hemigrammus micropterus MEEK Ms., Proc. U. 8. N. M., 1907, 33, p. 15 (Los Castillas); E1GENMANN, 
Rept. Princeton univ. exped. Patagonia, 1910, 3, p. 436. 
One specimen 10802 I 35 mm. Los Castillas, Venezuela O. Riddle 
Head 3.8-4; depth 3.2; D.10 or 11; A. 24; scales 4-32-4; eye 2.75 in 
the head, interorbital about equal to the eye. 
Compressed, depth of head at the base of the occipital process 1.5 in the 
greatest depth. Preventral region rounded, with complete median series of 
10 scales. Postventral region not so narrow as in most species of the genus. 
Predorsal region rounded with complete median series of 9 or 10 scales. 
Occipital process 5 or 6 in the distance from its base to the dorsal. Inter- 
orbital slightly convex. Frontal fontanel triangular and equal to the parietal 
without the occipital groove. Second suborbital in contact with the preopercle 
behind and below. Snout short and narrow, mouth rather small. Maxillary 
about equal to the eye. Mandible a little longer, 2.25 in the head. Pre- 
maxillary with an inner series of five, 5- to 7-pointed teeth and an outer 
series of two narrowly tricuspid teeth. Maxillary with one 7-pointed tooth. 
Dentary with a graduated series of five, 3- to 5-pointed teeth and a row of 
minute conical teeth on the sides. 
Gill-rakers 6 + 9. 
Anal sheath short, consisting of 1 or 2 scales. Lateral line with pores on 
4 or 5 scales. 
Origin of the dorsal equidistant from snout and caudal, the penultimate 
ray four ninths of longest which is 4 in the length. Origin of the anal on the 
vertical from the second scale back of the dorsal, anal slightly emarginate, 
1 One specimen from Lago do Maximo with a complete lateral line. 
