38 
Indiana University Studies 
anal rays 
scales 
23 
24 
25 
26 
27 
28 
29 
32 
33 
34 
35 
36 
37 
Moenkhausia dichroura 
17189, Rurrenabaque 
3 
4 
2 
1 
4 
6 
17192, Popoi River, Upper Beni 
2 
3 
3 
1 
Moenkhausia intermedia 
17193, Reyes 
2 
5 
3 
5 
5 
17196, Lake Rogoagua 
2 
1 
2 
3 
2 
Moenkhausia cotinho Eigenmann. 
17266, 1, 50 mm., Cachuela Esperanza. Mar., 1922. 
This specimen differs from the typical cotinho by having the 
third suborbital very much larger, partly in contact with the 
lower margin of the preopercle and meeting the second sub- 
orbital in a straight line. D.ll ; A.22 ; scales 5-30-3 V 2 ; lateral 
line complete. 
Knodus breviceps (Eigenmann). 
17242, 41, 20-66 mm., Espia. July, 1921. 
17243, 400, 38-62 mm., Rio Iniqui, Upper Beni. Sept., 1921. 
17244, 105, 30-52 mm., Popoi River, Upper Beni. Sept., 1921. 
17245, 286, 37-48 mm., Rurrenabaque. Oct., 1921. 
17246, 121, 32-45 mm., Rio Colorado, Lower Bopi. Sept., 1921. 
17247, 84, 20-63 mm., Huachi. Aug., 1921. 
17248, 1, 42 mm., Cachuela Esperanza. Feb., 1922. 
All the above specimens have the appearance of breviceps 
except that they are longer, the depth is 3% times in the 
length. The immature specimens may belong to another 
species. 
Markiana nigripinnis (Perugia). 
17162, 5, 125-140 mm., Reyes. Nov., 1921. 
These specimens were collected at the same locality from 
which Perugia secured his second lot of specimens. 
G y mnocory m bus thayeri Eigenmann. 
17340, 8, 22-30 mm., Cachuela Esperanza. Mar., 1922. 
Gymnocorymbus ternetzi (Boulenger) . 
17187, 1, 45 mm., Lagoons, Lake Rogoagua. Oct., 1921. 
17188, 6, 48-50 mm., Reyes. Nov., 1921. 
