210 THE AMERICAN CHARACIDAE. 



Humeral spot intense black, round, but with faint vertical elongations, 

 sometimes surrounded, more often followed, by a light area. Caudal spot 

 irregular, more intense on the fin than on the caudal peduncle, not extending 

 as far as half way to the end of the middle caudal rays. A narrow but intense 

 lateral stripe in the region above the anal, fading out just before it joins the 

 caudal spot and just in front of the vertical from the dorsal. A dark line along 

 the base of the anal. Fins all dusky, especially the anal and lower lobe of the 

 caudal. Scales all clearly outlined with brownish. Cheeks and back thickly 

 peppered with brown chromatophores. 



28. Hyphessobrycon duragenys Ellis. 

 Plate 30, fig. 1. 



Hyphessobrycon duragenys Ellis, Ann. Carnegie mus., 1911, 8, p. 15.5, pi. 2, fig. 3. 



Habitat. — Rio Parahyba and Rio Tiet6 Basins. 



Head 3.25-3.7; depth 2.5; D. 10 to 12; A. 16 to 18; scales 5 or 6-32 to 

 36-4 to 5; eye small, 3.0 to 3.5 in the head; interorbital wider than the length 

 of the eye, 2.8 to 3.2 in the head. 



Compressed. Depth of the head at the base of the occipital process 1.5 in 

 the greatest depth. Preventral and predorsal regions rounded, usually without 

 complete series of median scales. 



Occipital process about 5 in the distance from its base to the dorsal, bordered 

 by 3 or 4 scales. Interorbital only slightly convex. Frontal fontanel triangular, 

 as wide as the parietal, and one half to three fourths as long as the parietal 

 without the occipital groove. Second suborbital usually in contact with the 

 preopercle. Third suborbital about one half as wide as the eye. Mouth mod- 

 erately large; snout short. Maxillary equal to the eye. Mandible longer 

 than the eye, 2.5 to 3 in the head. Premaxillary with three or four tricuspid 

 teeth in the outer row, and a graduated series of five 3- and 5-pointed teeth in 

 the inner row. Maxillary with one tricuspid tooth. Dentary with a graduated 



