1905. ] AMPHIBIANS AND REPTILES. 209 
CROCODILIA. 
Crocodilus americanus is the commonest tropical American 
Crocodile, from Florida to Northern South America. In Mexico 
it is strictly confined to the Tierra Caliente, with Mazatlan as its 
north-western limit. It ascends the Rio Balsas at least up to 
Meseala, but this is not much more than 1700 feet above sea-level. 
Common in the lagoons on the coast of Guerrero and Oaxaca, 
except where it has recently been well-nigh exterminated by 
American skin-hunters. More exist in the river-systems of the 
State of Vera Cruz, ascending occasionally up to Motzorongo, 
i. e. 1500 feet. During the rainy season they often forsake the 
then turbid rivers, and roam at night through the forests in 
search of lagoons. 
CO. moreleti inhabits the Tierra Caliente from Tampico to 
Honduras. 
Caiman sclerops s. punctulatus has its centre in South America. 
In America it occurs only in the Atlantic hot-lands. I met with 
very large specimens (length of skull 20 inches) at Agua fria in 
the same lagoons and rivers as the Crocodile. Whilst the latter, 
anyhow not averse to brackish water, inhabits the Greater Antilles, 
the Caiman has found its way only into Trinidad and, if report 
is true, to Martinique. The Alligator of the southern United 
States does not seem to cross the Rio Grande. 
CHELONTA. 
It seems almost incredible that Chelydra has never been re- 
corded from Mexico, considering the wide range of Ch. serpentina 
in the United States and the existence of the other species, 
Oh. rossignoni, from Guatemala to Ecuador. The Papaloapan 
and 8. Juan Rivers of the State of Vera Cruz are certainly large 
enough, with pools and backwaters, but I could not ascertain the 
presence of a large, snappy species. 
DERMATEMYDID#.—The few species of this family are peculiar to 
Central America. Dermatemys mawi extends from Honduras 
into Yucatan and Vera Cruz; it occurs, for instance, in the pools 
of the forests and savannahs near Tetela, where it is known as 
the “Tortuga blanca.” Stawrotypus seems to have a similar 
range: S. triporcatus going up to Vera Cruz; S. biporcatus only 
up to the Isthmus. 
CINOSTERNIDH, with the sole genus Cinosternum. About 10 
species in North and Central America, one extending to Guiana. 
Well represented in Mexico by 6 species. Of these, C. pennsyl- 
vanicum, previously recorded from the Valley of Mexico, was. 
found by myself in South Guerrero, at San Luis Allende. 
O. hirtipes ranges from Arizona and New Mexico along the 
Pacific side into Jalisco, and includes the Tres Marias Islands. 
Proc. Zoou. Soc.—1905, Vou. Il. No. XIV. 14 
