1020 The American Naturalist. [December,. 
from the Canadian) ; two species and two subspecies of lizards ; 
and three species and eleven subspecies of snakes. 
We have of species and subspecies of the Western subregion 
the following synopsis: 
Peculiar to the Diegan district, . , : ; ; 19 
Common to the Diegan and Chihuahuan, : 6 
Common tothe Diegan and Pacific, . 5 ae 
Peculiar to the Pacific, . : i 39 
75 
VIII. Tue TOLTECAN SUBREGION. 
This subregion includes three districts which possess charac- 
teristic species, and which differ in climate. The Austroriental 
is a humid region with abundant rains and fogs, and includes 
the eastern face and slope of the central plateau, with the 
mountain elevations, including parts of the States of Puebla, 
Vera Cruz, Hidalgo and San Louis Potosi. It is cut off to the 
north from the Austroriparian subregion by an interval in the 
States of Nuevo Leon and Tamaulipas. The middle or Aus- 
trocentral district includes the valleys of Mexico and Toluca, 
and the region northward to the edge of the Sonoran subregion, 
including the State of Guanajuato, and perhaps further north. 
The climate of this district is much less humid than that of 
the Austroriental district. The Austroccidental district includes 
the high lands of Oaxaca, Guerrero, Michoacan and Jalisco. It 
is the most arid of the three divisions, and extends furthest to 
the south and west. 
The northern boundary of the Toltecan district is not yet 
determinable ; hence it is not possible to state whether species — 
from the States of Durango and Zacatecas, such as Eutænma 
angustirostris, should be referred to it or not. A small collec- 
tion made by Wilkinson in southern Chihauhua at Batopilas’ 
has the character of the Chihuahuan fauna, with the following ; 
species not otherwise found in it: 
Anolis nebulosus Wiegm. Scolecophis æmulus Cope. 
Uta bicarinata Dum. 
1 Cope, Proceeds. Amer. Philosoph. Soc., 1879, p. 261. 
ee 
