1905. ] AMPHIBIANS AND REPTILES. 197 
Xochimileo freshwater, surrounded by meadows, wooded hills 
with streams. 
Sierra de Ajusco, volcanic, well-wooded mountains. Contreras, 
8090'; Dos Rios, 8800’, pines. Orizaba, 4027’; on the east side 
of the slope of the plateau; valley with streams, pastures, and 
rich vegetation, on alluvial and hard-limestone terrain. Thence 
gradual ascent to the volcano Citlaltepetl; dense mixed forest, 
oak, arbutus, and pines, about 9000’; giving way entirely to pines. 
Tree-line about 13,500’; then tussocks of grass. Snow-line about 
14,500’. 
Cordoba, 2700’. Dense tropical vegetation. Thence south- 
wards, through limestone terrain, along the foot of the slopes, 
which are covered up to the edge with luxurious forests ; east- 
wards bordered by savannahs. Permanent rivers with high 
banks ; lagoons in the forests and savannahs. 
Motzorongo, Presidio, and La Raya, about 1500’, in forest land. 
Tetela, about 900’, near the edge of the savannah. 
Agua fria, 100-200'; lagoons, swamps, and low forest; flat 
country, subject to inundations. The Rio Papaloapan, with its 
many tributaries, carries an enormous volume of thick, yellow 
water; much of the lower basin is for months under water, only 
island-like parts standing out, used as refuges, although by no 
means sanctuaries, by the game and other creatures. 
Then follows low, undulating, rolling, cattle-grazing land, with 
sandy subsoil. 
San Juan KEHvangelista, 100’. Tropical river-bed through 
savannahs, bordered by dense lowland forest. 
Isthmus of Tehuantepec. Eastern slope, dense humid ever- 
green forest; on the ridge, less than 1000’, open country with 
temporary stagnant lagoons; on the western slope prevails the dry 
Pacific type without continuous forests, but with more scattered 
patches of mostly deciduous trees. 
Tehuantepec, 120'. Sandy, varied terrain. 
San Mateo del Mar. Sandy, lagoons connected with the sea. 
Flat, scanty vegetation except in occasional swamps or near the 
lagoons, some of which are fringed with dense low brushwood 
and small trees. 
Salina Cruz. Porphyritic terrain; hilly, steep coast-range, varied 
by promontories and fresh- and salt-water lagoons. 
From Salina Cruz and Tehuantepec northwestwards to Oaxaca. 
The coast-range, averaging 2000-3000 feet, is covered with 
pines down to 2000 feet. Tequesixtlan, 560’, in a river-valley, shut 
off by the coast-range; varied, rather low vegetation, volcanic 
alluvial. Thence through mountainous country, across parallel 
ridges. Hills at first with tropical vegetation; oak-forests from 
3000’ upwards, then pines prevailing, but nowhere continuous 
forests. General character of the country dry, most of the smaller 
rivers run dry except in the rainy reason. An intricate system of 
