Pearson: Fishes of the Rio Beni Basin 
35 
5 — 34 to 37 — 3 ; premaxillary teeth 4 ; maxillary 5 to 7 ; man- 
dibular 7 or 8. Eye 3.5 in the head, about equal to the snout, 
a little less than the interorbital; base of anal equal to the 
head less the opercle ; depth of caudal peduncle a little more 
than 2 in its length. Snout rounded, gape horizontal ; toothed 
part of the maxillary longer than the toothless part, the latter 
decurved, reaching beyond the anterior margin of the eye; 
second suborbital strongly convex. About 11 short and slender 
gill rakers on the lower gill arch. 
Origin of dorsal a little nearer caudal than snout; pectorals 
reaching to the third scale in front of ventrals ; origin of ven- 
trals nearer snout than caudal, their tips just reaching anal; 
caudal deeply emarginate. 
3. Dentition of Monotocheirodon pearsoni Eigenmann 
Scales regularly imbricate; one scale projecting up on the 
anterior part of anal ; caudal with a large thin scale on each 
lobe and smaller ones on the base. 
A black spot crossing the third scale of the lateral line; a 
dark, lateral band; sometimes a small dark spot on the base 
of the middle caudal rays, separate from the lateral band and 
much narrower ; back and opercle profusely dusted. 
Prodontocliarax Eigenmann & Pearson, gen. nov. 
Adipose fin present; lateral line complete; teeth mostly 
tridentate ; premaxillary vertical or sloping backward, with 5 
to 7 teeth ; maxillary short, its margin at an angle with the 
margin of the premaxillary, with 5 to 7 teeth; teeth of the 
6—30279 
