CHARACINIDAE FROM VENEZUELA—SCHULTZ 253 
interorbital width 2% to 3% in length of head; palatines with or without 
teeth; distance between rayed dorsal and adipose fin 1 to 1% in base of 
former. 
3a. Palate toothless, sometimes roughened or with a few blunt, rudimentary 
teeth; second suborbital not or not much deeper than eye, separated 
from angle of preoperculum by a space equal to 14 to % diameter of eye; 
base of adipose fin 324 to 4% in that of rayed dorsal, which is 3% to 3% 
in depth of body; distance between rayed dorsal and adipose about 
equal to base of former. 
4a. Depth about 134 in standard length, head about 3%; eye 333 to 3% in 
head; origin of dorsal a little nearer base of caudal than end of snout. 
Serrasalmus scapularis Giinther 
4b. Depth about 1% in the length, head 3% to 3%; eye about 4 in head; 
origin of dorsal equidistant from end of snout and base of caudal. 
Serrasalmus serrulatus (Valenciennes) 
3b. Palate with well-developed teeth. 
5a. Second suborbital broad, narrowly separated from preoperculum in 
adults. 
6a. Dorsal with 14 to 19 rays; anal 32 to 37 rays; snout shorter than eye 
in adults; base of adipose fin 2%4 to 4 in that of rayed dorsal; snout 
blunt; interorbital width 2% to 2% in length of head; last simple 
ray of anal distinctly thicker than first branched ray; caudal fin 
generally with a black submarginal band. 
Serrasalmus spilopleura Kner 
6b. Dorsal with 20 rays; anal with 27 rays. 
Serrasalmus caribe Valenciennes 
5b. Second suborbital rather narrow, separated from angle of preopercle by 
a space equal to about % (or more in young) of eye; depth 1% in 
length; head 3; base of anal 2% in length to base of caudal fin; dorsal 
rays li, 14 or 15; anal rays iii, 29 to 31; ventral serrae 22 to 24-+10 or 
11; base of caudal fin blackish__Serrasalmus eigenmanni Norman 
1b. Premaxillary teeth in two series; mandibulary teeth in a single series; some- 
times a pair of conical teeth behind and in contact with symphyseal 
mandibulary teeth; abdomen serrated before and behind pelvics; teeth 
more or less close-set, either incisorlike or with an oblique cutting edge or 
molariform; each premaxillary with 5 teeth in outer and 2 in inner series; 
jaws equal or lower, a little projecting; conical mandibulary teeth present. 
7a. No predorsal spine. 
8a. Supplementary scales, if present, small and confined to hinder edges of 
primary scales; anal fin with a basal sheath of scales and with highest 
rays anteriorly (Colossoma); gill rakers 15 to 18 on lower half of first 
arch; 65 to 69 ventral serrae; base of adipose fin 5 to 6% in that of 
rayed dorsal, base of dorsal 4% to 5% in standard length; adipose fin 
rayed in adults. 
9a. Head a little more than 3 in standard length in adults; breadth of 
operculum more than one-half length of postorbital part of head; 
suborbital and opercular bones rather smooth; second suborbital 
almost entirely covering cheek; about 80 scales from head to caudal 
LOE HS s\\ MN i Lt a el EN Sy aN A Colossoma macropomus (Cuvier) 
9b. Head 3% to nearly 4 in standard length in adults; breadth of oper- 
culum less than one-half length of postorbital part of head; suborb- 
ital and opercular bones rugose; second suborbital separated from 
