144 THE AMERICAN CHARACIDAE. 
the head. Origin of the anal on the vertical from the eighth or ninth dorsal 
ray. Ventrals on a vertical from the first or second scale in front of the dorsal. 
Ventrals reaching just to the anal. Pectorals reaching to the ventrals. 
The distal three fourths of the first, second, and third, and distal one fourth 
of the fourth dorsal rays pigmented. An oblique blackish line passing over 
the basal fifth of the third, the entire fourth and fifth, and the tips of the sixth 
and seventh anal rays. The first and distal half of the second and third anal 
rays, with intervening membrane, with a milk-white elongate spot. A very 
slender dark gray lateral stripe from the caudal peduncle to the vertical from 
the dorsal. A few chromatophores, much scattered and very faint, occur in 
the humeral region. The one 35 mm. specimen from Tapajos differed from 
the rest in the anal marking. In it the oblique line was lacking, giving place 
to a semicircular dark spot including the tips of the sixth, seventh, and eighth 
rays. 
5. H®rMIGRAMMUS ERYTHROZONUS Durbin. 
Plate 21, fig. 4. 
Hemigrammus erythrozonus DurBin, Ann. Carnegie mus., 1909, 6, p. 56 (Erukin); Ercenmann, Rept. 
Princeton univ. exped. Patagonia, 1910, 3, p. 436; Mem. Carnegie mus., 1912, 5, p. 333, pl. 48, fig. 2. 
Hasirat.— British Guiana. 
Specimens examined. 
Number of 
Catalogue number specimens Size in mm. Locality Collector 
1448 C. Type 1 32 Erukin Eigenmann 
ees Soe t 32 21-33 Erukin Eigenmann 
Head 3.75; depth 3.33 to 3.75; D.11; A. 20-22; scales 5-31 to 34-3 to 
3.5; eye 2.5 in the head, snout 1.5 in the eye. Interorbital less than eye, about 
2.75 in head. 
Compressed; depth of head at base of the occipital process 1.5 in the 
greatest depth. Preventral region rounded, without complete, regular series 
of median scales. Predorsal region rounded, median series of scales incom- 
plete, always more or less irregular near the head. 
Occipital process from one sixth to one seventh of the distance from its 
base to the dorsal; bordered by 3 scales. Interorbital convex. Frontal 
fontanel much narrower than parietal, triangular, two thirds of the parietal 
