242 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 95 
24b. No teeth on lower jaw, but upper jaw with a single row of 20 
to 30 pluricuspid, incisorlike teeth; gill membranes free 
from each other and from isthmus; lateral line complete; 
premaxillary not protractile; eye in a sheath or adipose 
lid with small circular opening; pelvics inserted under 
middle of dorsal base and dorsal origin closer to snout than 
base of: caudal) fines oe Hemiodus Miller (p. 291) 
24c. Middle of lower jaw with teeth and without hard cartilag- 
inous edge. 
25a. Teeth in two rows in lower jaw, inner row sometimes 
represented by a pair of teeth near symphysis or a row 
of minute teeth; pelvics inserted in front of a vertical 
line through dorsal origin. 
26a. Adipose fin present. 
27a. Teeth on premaxillary in one or two rows, the inner 
row on dentary formed by a series of minute teeth 
directed inward. 
28a. No canines in either jaw; gill membranes free from 
isthmus but partially united forward with a 
narrow free fold across it; base of anal fin with 
a sheath of seales. 
29a. Teeth tricuspid; premaxillary teeth in one row, 
those at front similar to outer row of dentary 
and numbering 9 to 11 on a side; caudal fin 
scaled two-thirds the way out, only a wide 
margin scaleless; upper caudal lobe longest; 
lateral line obsolete. 
Piabucina Valenciennes (p. 291) 
296. Teeth conical, short, in two rows in both jaws; 
maxillary with a single row along its entire 
edge; maxillary slipping under preorbital and 
reaching to rear of eye; lateral line complete, 
a little decurved anteriorly; caudal scaled a 
a little at its midbase. 
Salminus Agassiz (p. 293) 
286. Both jaws with several canine teeth as follows: 2 
pairs on premaxillaries and 4 or 5 pairs on den- 
taries; no small conical teeth between canines on 
lower jaw; inner series of teeth of dentary con- 
fined to front of jaw; anterior half of upper 
portion of first gillarch with rough plates instead 
of elongate gill rakers. 
Cynopotamus Valenciennes (p. 295) 
276. Teeth tricuspid, in 3 rows on premaxillaries, inner row 
on dentary formed by a pair of enlarged teeth at 
symphysis; maxillary long, narrow with a series of 
teeth along its entire edge; lower jaw included; gill 
rakers numerous, slender; lateral line complete; 
dorsal origin in front of that of anal. 
Brycon Miller and Troschel (p. 307) 
26b. Adipose fin absent; top of head flat; no canines; lower 
jaw longest, mouth oblique, short; dorsal fin behind 
middle of length of body without tail; anal with a 
