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Show 1 9 0 5 .] AMPHIBIANS AND REPTILES. 2 2 3 Pacific, terrestrial xerophile, and a more Atlantic and southern rather hygrophile stock. The former is almost typically Sonoran, except that it does not enter the plateau. Since Charina shows that it can endure a cold climate, the absence of similar forms on the Mexican plateau may possibly date back to the barrier of volcanic terrain. C o l u b r id .e .- Of the bewildering number of these snakes in Mexico only those have been selected for discussion which seem to yield some tangible results, while such as are too widely scattered or rather imperfectly known in their distribution have been mostly left out. C. a g l y p h /E.- Tropidonotus, decidedly a Nearctic genus, extending through the whole of Mexico, with greatly diminishing numbers of species into Central, but not into South America or into the Antilles. T. ordinatus (incl. varieties) is the commonest species in the whole of Mexico. T. vcdidus is a western form, from Utah to Colima, T. sipedon s. fasciatus is eastern, from east of the Rocky Mountains to Costa Rica. Others are confined to the southern half of Mexico. Ischnognathus is Nearctic, extending over the plateau, re-occurring in Guatemala. Contia, clearly Nearctic, through Mexico, with preference for the plateau and its western slope, into South America. Ficimici is Sonoran, scattered through Mexico. Zamenis.-Sonoran. Of the 9 American species, 8 occur in Mexico, 3 of which are confined to the southern half or extend into Central America, but not into the Antilles. Z. constrictor, widely spread over the States, enters North Mexico. Z. ornatus, semilineatus, and tceniatus are typical of New Mexico, Arizona to Sinaloa, continuing as Z. mentovarius as a western form from Sinaloa, Colima, S. Oaxaca to Guatemala. Z. grahcimi is a central and eastern form from the Southern States right over the plateau and the East to Tehuantepec. Z. pidcherrimus is southern, from Salina Cruz to West Nicaragua; lastly, Z. mexicanus has been recorded from Colima, Central and South Guerrero, Guanajuato, and from Cape Corrientes in Jalisco *. Coluber with Spilotes and Fityophis are clearly Nearctic, with some species in almost every State of Mexico ; none is Antillean, although some extend far into South America. C. corais, the most powerful Colubrine Snake of Mexico, inhabits the warm and hot countries, with the wide range from the South-eastern States of North America to Brazil. Coronella.-Nearctic. C. regcdis from Kansas, over the plateau to Mexico City ; C. Icevis in Nuevo Leon ; C. annidcita = micropholis from Texas to Para, in Mexico certainly all over the * Bocourt (Mission Scient. Mex.) states emphatically " au cap Corrientes sur le Pacifique " ; it is therefore rather perplexing that Gunther (Biol. Centrali-Americ.) adds " Cuba, Mus. Paris," as a locality of this species. There happens to be a Cape Corrientes at the western end of Cuba. |