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Show 2 1 0 DR. H. GADOW ON MEXICAN [June 6, C. sonoriense in Sonora. C. integrum (a variety of C. scorpioides) is likewise Pacific, from Jalisco, e. g. Lake Chapala, to which I can now add Zapotlan and the small rivers on the plateau south of Oaxaca and the swamps of San Mateo near Tehuantepec. C. leucostomum extends from New Orleans along the Atlantic side of Mexico through and beyond Central America. C. efeldti is known from the State of Vera Cruz, San Mateo del Mai, and Guatemala. T e s t u d in id /E.-Cistudo with two species in North America and one in Yucatan, strictly terrestrial. C. mexicana of Texas and New Mexico, e. g. San Marcial. How far it extends into Mexico is not known ; Tampico is quite possible, but I very much doubt " Mexico City" and neighbourhood. Nicoria rutila I have met in swampy bush-land of the State of Vera Cruz and near Tehuantepec, and this seems to be its range; allied species occur in Central America. Chrysemys extends from Canada to Argentina, but with a preponderance of northern forms. In Mexico restricted to the hot countries, and even there common only about the Isthmus, whence C. grayi - umbra and C. incisa go further south. C. ornata, from Panama to Tehuantepec, has been found by Forrer also near Mazatlan, with C. pulcherrima. I do not know of a single locality for Chrysemys 011 the plateau, or to the east of it, except for C. mobiliensis, which goes from Texas into the lowland of Nuevo Leon. This scarcity of Water-Tortoises in Mexico is rather puzzling. On the plateau Cinosternum alone is found, and these thick-shelled box-like creatures are, moreover, the only kind which can withstand the buffeting to which they are subjected in the torrents into which the rivers of the slopes of the plateau are converted in the rainy season. The Tortoises hide then under the boulders in the stream. Chrysemys shuns such waters, and neither it nor Cinosternum occurs in those rivers which carry much sand. Chelone viridis was laying during July and August 011 the coast of Guerrero and Oaxaca. Resume of the Distrib u tion of Mexican Chelonia. The Cinosternidse, taken with the closely-allied Dermatemydkke and Chelydridse, are autochthonous Americans; the first a Sonoran, the second obviously a southern group so far as the present distribution is concerned. Both Clielydrids and Dermatemyds are known from the Cretaceous of North America. The three together may well be regarded as originally northern and ancient. The same applies to the Testudinidse, the only family which has, recently, sent a United States Chrysemys into the Antilles and a South American into the Windward Islands. The Testudinidse, plentiful in North America, scarce in Central, and with still fewer species in South America, have clearly come from the |
