ANIMALS. 
The fauna of Mexico presents many of the characteristics of 
a district, where the natural distribution and locality of animals 
is less interfered with than in other places on this continent. 
The tropical exuberance of the vegetation, the uncleared condi- 
tion of the ground, arising from the absence of agricultural opera- 
tions, and the scattered population, leave the surface in the undis- 
turbed possession of mammal, reptile, bird, and insect. There is 
here an abundance of reptile life, with the processes actively 
going on which diminish their excessive numbers. The countless 
myriads of insects threaten, by their prolific powers, to overrun 
the whole land, but the elevated hills of these districts afford the 
grand barrier to their distribution ; they are confined to a zone of 
the air above which they do not travel, and into which they are 
pursued by the insectivora. Many of these animals will, no 
doubt, disappear upon clearing the ground ; but still those useful 
will ever be retained, and serve to administer additional and 
peculiar aid to the wants of man, and add to the riches of the 
country by the exportation of the produce derived from their 
growth. 
The domestic animals at present found on the Isthmus are, 
with rare exceptions, not indigenous, but were introduced from 
Europe in the sixteenth century, or at periods subsequent to the 
conquest of the country by the Spaniards. Some of these have 
since multiplied to a surprising extent, particularly horses, mules, 
and cattle, which are found in the greatest numbers throughout 
the inhabited parts. 
The immense potreros which border all the principal streams 
on the northern division, furnish rich pastures of never-failing 
