Pearson: Fishes of the Rio Beni Basin 
41 
species A. simulatus which has the chromatophores collected 
along the posterior edge to form lateral bands. 17173 has 2 
or 3 more anal rays than the types. Heretofore described only 
from the Paraguay system. 
Astyanax guaporensis Eigenmann. 
17322, 12, 27-44 mm., Lagoon near Eeyes. Nov., 1921. 
Ctenobrycon hauxwellianus (Cope) . 
17294, 187, 25-74 mm., Cachuela Esperanza. Mar., 1922. 
17295, 15, 45-60 mm., Reyes. Nov., 1921. 
17296, 9, 27-48 mm., Rurrenabaque. Oct., 1921. 
17297, 3, 50-68 mm., Lagoons, Lake Rogoagua. Nov., 1921. 
17298, 5, 48-52 mm., Huaehi. Aug., 1921. 
17299, 2, 44-46 mm., Popoi River, Upper Beni. Sept., 1921. 
All of the above specimens have the lateral line complete. 
This agrees with other specimens taken from various locali- 
ties in the Amazon basin of which Dr. Eigenmann examined 
1,400. In this respect they show no relation to specimens 
taken in the Paranahyba in which the lateral line is said to 
“stutter.” 
Astyanacimis moorii (Boulenger). 
17180, 19, 55-76 mm., Tumupasa. Dec., 1921. 
17181, 24, 54-95 mm., Popoi River, Upper Beni. Sept., 1921. 
17182, 5, 52-78 mm., Ixiamas. Dec., 1921. 
17183, 13, 45-70 mm., Huaehi. Aug., 1921. 
17184, 3, 54-100 mm., Rurrenabaque. Nov., 1921. 
Astyanacimis muitidens Pearson, sp. nov. Plate IX, fig. 4. 
17323, cotypes, 22, 95-140 mm., Rio Colorado, Lower Bopi. Sept., 1921. 
17324, 2, 64-96 mm., Popoi River, Upper Beni. Sept., 1921. 
17325, I, 76 mm., Tumupasa. Dec., 1921. 
17326, 1, 83 mm., Rurrenabaque. Oct., 1921. 
Head 3 2/3 to 4 ; depth 3 to 3 1/3 ; D.ll ; A.28 to 31 ; eye 3 1/2 
to 414 ; lateral line 7 or 8 — 39 to 41 — 7 ; 3 or 4 teeth in the outer 
series of the premaxillary, 5 in the inner row; mandible with 
4 large teeth in front and then followed abruptly by smaller 
teeth on the sides; maxillary with about 11 teeth along almost 
the entire border; maxillary-premaxillary border 1/2 the 
length of the head ; the third suborbital with a wide naked 
border ; about 12 gill rakers on the lower gill arch, their length 
equal to 1/2 the diameter of the eye ; interorbital convex ; pre- 
