1905.] amphibians and reptiles. 209 



Crocodilia. 



Crocodihts americanua is the commonest tropical American 

 Crocodile, from Florida to JSTorthern 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 np to 

 Mescala, 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. 



C. moreleti inhabits the Tierra Caliente from Tampico to 

 Honduras. 



Caiman sclerops s. 2>unctulatus 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 Ti'inidad and, if report 

 is true, to Martinique. The Alligator of the southern United 

 States does not seem to cross the Rio Grande. 



Chelonia. 



It seems almost incredible that Chelydra has never been re- 

 corded from Mexico, considering the wide range of Ch. seiyentina 

 in the United States and the existence of the other species, 

 Ch. rossignoni, from Guatemala to Ecuador. The Papaloapan 

 and S. 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 maivi 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." Staurotypus seems to have a similar 

 range : S. triporcatus going up to Yera Cruz ; aS'. 'bip)orcatus only 

 up to the Isthmus. 



CinosterniDjE, with the sole genus Cinostermmi. About 10 

 species in Korth and Central America, one extending to Guiana. 

 Well represented in Mexico by 6 species. Of these, C. pennsyl- 

 vanicum, previously recorded from the Yalley of Mexico, was 

 found by myself in South Guerrero, at San Luis Allende. 

 C. hirtip)es ranges from Arizona and New Mexico along the 

 Pacific side into Jalisco, and includes the Tres Marias Islands. 



Proc. Zool. See— 1905, Yol. II. No. XIY. 14 



