172 THE AMERICAN CHARACIDAE. 
or 4 normal scales which extend over the bases of the first 7 or 8 rays. Pores 
developed on 7 or 8 scales. 
Origin of the dorsal about equidistant from the snout and caudal, the 
penultimate ray 0.4 of the longest which is 3.67 in the length. Origin of the 
anal on the vertical from the second scale behind the dorsal; anal emarginate, 
longest ray equal to the base. Caudal half the length of the eye longer than 
the head. Ventrals on the vertical from the first dorsal ray; ventrals just 
reaching the anal. Pectorals not reaching the ventrals. 
Humeral spot distinct but not heavy, not conspicuously elongated. Lat- 
eral stripe the width of one scale, not so intense as the humeral spot, expanded 
on the caudal peduncle, but not extending on the fin; scales overlying the 
lateral stripe distinctly silvery. No caudal spot. First five anal rays, the 
caudal and all of the dorsal dusky. Each median dorsal scale with a roundish 
dark spot. Scales of the upper half of the sides outlined with dusky. A few 
chromatophores scattered about the base of the anal and aggregated so as to 
form a small dark spot or line on the ventral side of the caudal peduncle. Top 
of the head dark. The lateral stripe probably red in life. 
The single specimen from Santarem resembles very closely H. analis, and 
has 13 anal rays, but the maxillary has but one tricuspid tooth which is not 
typical. 
10. HypnHrssoprycon Durbin. 
igjoowv = smaller, Bpvxw = to gnash the teeth, from which Brycon a genus of Characins. 
Hyphessobrycon Dursin, Bull. M. C. Z., 1908, 62, p. 100 (compressus). 
Dermatocheir Dursin, Ann. Carnegie mus., 1909, 6, p. 55, (catablepta). 
Typn.— Hemigrammus compressus Meek. 
Like Hemigrammus but with the caudal naked. 
The genus Dematocheir was based on a specimen with arrested pectoral 
development. Several other species have since been discovered with similar 
pectorals, but otherwise showing the characters of this and of other, quite 
distinct genera. 
Hasrrat.— Mexico to the La Plata, Pacifie Slope of Ecuador. 
; Key to the Species. 
a. Scales 45-48, no lateral band, no caudal or humeral spots. D.11; A. 25-27; scales 8-45 to 48-7. 
b. Dorsal with a conspicuous spot on basal half of anterior rays; maxillary equals eye. 
seh, 1. compressus (Meck). 
bb. Dorsal’dark; anal mostly dark; maxillary less than eye; everywhere densely peppered with 
GHTOMAPOPNONED | i, wai aie Ss sie tote se a attee oaMRRN iE serie In lce atte en chen 2. milleri (Durbin). 
