XX INTRODUCTION. 
Tortoise, which will bear a greater degree of cold than that 
of most of our winters, without perishing ; and it is cer- 
tainly desirable that a wholesome and agreeable food, like 
that afforded by some of these, should. not be lost to us, 
if the species can be easily perpetuated and multiplied in 
our climate. 
Of the third order of Reptiles, to which the term Zori- 
cata has been given, on account of the peculiar coat of hard 
mail with which all the species are covered, we have 
happily no indigenous example, nor would any of them 
bear the cold of our climate. The Crocodiles and Alliga- 
tors of both worlds, and the Gavials of India, constitute 
this order. They are distinguished from the true Saurians, 
or Lizard tribe, by several important characters. Of these, 
the most tangible and obvious is that upon which the name 
of the order is founded; the covering of the whole of the 
back part of the neck, body, and tail, with distinct series 
of bones, of moderate size, embedded, as it were, im the 
substance of the skin, and covered externally with a thick 
cuticle. These dermal bones are usually furnished with a 
crest, which renders them exceedingly strong, and they 
altogether form a panoply of defence which can resist the 
attacks of the most powerful enemies of whatever kind. 
These animals are carnivorous, taking their prey generally 
in the water, but retiring to the shore to devour it, which 
they often defer until it has become half putrid. For the 
reasons given above, I do not think it necessary to enter 
into particulars respecting the structure and history of 
these animals. They can never become of local interest 
to us, as they are not made subservient to any purpose of 
utility to man, nor can they be naturalized in our latitude. 
The true Saurians are characterized by the existence of 
both anterior and posterior extremities, and of a moderate 
