1905. | AMPHIBIANS AND REPTILES. 223 
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. 
CotuBRrip#®.—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. AcLyPHm.—Tropidonotus, decidedly a Nearctic genus, ex- 
tending through the whole of Mexico, with greatly diminishing 
numbers of species into Central, but not into South America or 
into the Antilles. 7. ordinatus (incl. varieties) is the commonest 
species in the whole of Mexico. 7. validus is a western form, 
from Utah to Colima. 7. 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. 
Ficimia 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. 7. constrictor, 
widely spread_over the States, enters North Mexico. Z. ornatus, 
semilineatus, and teniatus are typical of New Mexico, Arizona to 
Sinaloa, continuing as Z. mentovarius as a western form from 
Sinaloa, Colima, 8. Oaxaca to Guatemala. 7%. grahami is a 
central and eastern form from the Southern States right over the 
plateau and the Hast to Tehuantepec. Z. pulcherrimus is southern, 
from Salina Cruz to West Nicaragua; lastly, 7. mexicanus has 
been recorded from Colima, Central and South Guerrero, Guana- 
juato, and from Cape Corrientes in Jalisco *. 
Coluber with Spilotes and Pityophis are clearly Nearctic, with 
some species in almost every State of Mexico; none is Antillean, 
although some extend far into South America. (©. 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. j 
Coronella.—Nearctic. C. regalis from Kansas, over the plateau 
to Mexico City; C. levis in Nuevo Leon; C. annulata = 
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 Gtinther (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. 
