DISTRIBUTION OF THE FISHES 43 
Lake Poop6, the recipient of the waters of Titicaca through the Desaguadero, 
in turn spills over into the flat salt marshes of Coipasa where there is sufficient area 
to provide for the evaporation of the excess. 
Region G, the northernmost one of the Montana extends from the crest of the 
Eastern Cordillera. It may be characterized by the great size and number of its 
network of streams, a plexus of active and backwater rivers, channels, oxbow- 
lakes, ete. All the eastern rivers of the region trend northward to the Maranon, 
parallel to the cordilleras, while those of Oriental Ecuador enter the same river 
from the northwest, spread out fanwise. It is a region of high rainfall, high hu- 
midity, and high temperature. Except for good-sized areas of grassland such as 
the Pampa de Sacramento, it is a tropical forest. Navigation is practicable to 
good-sized steamers for many hundreds of miles of the Maranon, Huallaga, and 
Ucayali. 
Region H is the least explored, consisting of rather broken terrain about the 
headwaters of the Jurua, the Purus, etc., and except for the eastward slopes of the 
cordillera is tropical lowland forest. It is difficult of access by trail, and very 
remote from bases in Brazil for approach by river. 
Region I consists of the Atlantic slopes of the Eastern Cordillera in Bolivia, 
very rugged terrain, but largely explored for minerals. The summits are often 
more mature and are used, together with the limited hillside lands and valley 
floors for agriculture. Rough trails follow the precipitous streams to the lowlands. 
This area was explored for fishes by N. E. Pearson on the Mulford Expedition. 
(1924.) 
The barriers separating the oriental regions are slight, and not effective for 
land forms. In fact the climatic zones follow vertical cleavage much more sharply 
than horizontal. All three of the Atlantic provinces are sparsely populated. Cot- 
ton, ivory nut, and rubber are typical products of the lowlands; coca, balsa-wood, 
sugar-cane and quinine of higher terrain. 
FAUNAL LISTS OF THE PRINCIPAL RIVER SYSTEMS 
LOWER MARANON 
PONGO DE MANSERICHE TO TABATINGA 
Bunocephalus aleuropsis Pimelodella puruensis 
z melas a lateristriga 
21 haggini “  buekleyi 
* coracoideus . hasemani 
Callophysus macropterus cristata 
Pimelodina flavipinnis os cyanostigma 
Microglanis zonatus Pimelodus pictus 
Zungaro zungaro jivaro 
Chasmocranus peruanus ee clarias 
Rhamdia quelen Goeldiella eques 
8 bathyura Pseudoplatystoma fasciatum 
_ humilis Phractocephalus hemiliopterus 
“c 
dorsalis Sciades marmoratus 
