Pearson: Fishes of the Rio Rent Basin 
19 
Hoplosternum littorale (Hancock) . 
17234, 2, 155 and 180 mm., Reyes, Bolivia. Nov., 1921. 
17233, 21, 15-195 mm., Lagoons, Lake Rogoagua, Bolivia. Nov., 1921. 
There are 6 immature specimens 15 to 25 mm. that I col- 
lected at the same locality as the adults. I am not sure that 
they are the same as there are no intermediate stages. The 
scutes are just beginning to form in the smallest. They ex- 
tend the entire length but they extend only half way from the 
lateral line to the mid-dorsal and mid-ventral lines. The head 
and the body covered with many chromatophores, thickest on 
the top of the head and back, 5 narrow light stripes across 
the back and extending on the sides, the first just in front of 
the dorsal, the second in front of the middle of the dorsal, the 
third just back of the dorsal, the fourth in front of the adipose, 
the fifth between the adipose and the base of the caudal. 
Sometimes the chromatophores are gathered to form small 
black streaks and spots between the light stripes, but these 
are not regular. A specimen 32 mm. long has the lateral 
scutes completely formed. In this specimen there are ir- 
regular small black spots over the body and the fins. On the 
caudal they are collected into bars. 
Corydoras latus Pearson, sp. nov. Plate III, fig. 1. 
17278, 1, type, 64 mm., Lagoons, Lake Rogoagua. Nov., 1921. 
Head 3 2/3; depth 2 2/5; D.I,8 ; A. 1,7 ; lateral plates 21-22; 
eye 3% ? maxillary barbels just reaching the gill opening; body 
deep, rather strongly compressed its entire length; origin of 
dorsal very slightly nearer the tip of the snout than the tip of 
the adipose, its distance from the tip of the snout 2 in the 
total length, its height equal to 5/6 the length of the head and 
just equal to the length of the pectoral spine; the pectoral 
spine just reaching the base of the ventrals ; two azygos plates 
in front of the adipose; caudal forked, the lobes 11/3 times 
as long as the head; the dorsal when depressed reaching to 
within two plates of the adipose. 
General color blackish; all fins uniformly dark, all fins ex- 
cept the pectorals with a maroon tinge; a row of light dots 
above and below the lateral line, the dots due to the absence 
of chromatophores on the posterior edge of the scute. Above 
and below the dots the chromatophores spread out so that 
there is formed a dark stripe along the meeting lateral 
4—30279 
