ANNOTATED LIST OF THE SPECIES 217 
16196, many, 36-108 mm., Rio Tingo, Hudnuco, Allen, October, 1918. 
16198, many, 51-110 mm., Rio Huallaga, Hudnuco, Allen, October, 1918. 
16199, many, 44-112 mm., Rio Chinchao, Piedra Blanca, Allen, October, 1918. 
16120, , below Cayumba rapids, Allen, October, 1918. 
16121, 9, 61-117 mm., Rio Huallaga, Ambo, Allen, October, 1918. 
16122, 14, 49-91 mm., Chumatagua creek, above Cayumba rapids, Rio Huallaga, Allen, September, 
1918. 
The above specimens taken from Chumatagua creek at about 2000 feet, Rio 
Chinchao nearer 2500 feet, the Hudnuco district at about 6000 feet, and from Ambo 
near 7500 feet, all records from above the barrier, or pongo, of the Huallaga, the 
rapids of Cayumba. 
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Fic. 25. Fish weir of Oriental Peru. This trap is placed across the mouth of a bayou or chan- 
nel. Fishes of large size press open the door suspended in the pound at the center, and are unable 
to open it the other way. 
Fishes of rapid mountain streams, with rock ledges, pools, and riffles, in and 
about the upper rain forest zone. It is a region in which a true dry season is want- 
ing, and in which almost daily rains occur. The streams tumbling down the moun- 
tain sides have almost daily freshets, and subside again as rapidly, in the section 
about the Cayumba rapids, although about Hudnuco and Ambo the species has 
entered the fringe of a more distinct wet and dry season area. 
Osgood obtained a specimen at Moyobamba and Pearson a number of them 
in the upper Maranon. Pearson also found the species common at elevations near 
1500 feet on the Rio Beni, Bolivia. 
Head 4.5; depth 3.0; D. 10; A. 30, twenty-nine and thirty-one in a few cases; 
