NATURAL HISTORY. 



399 



even the covering of the eyes. A rent opens in the neck, and 

 the snake, by entangling itself in the thick grass or bushes, 

 actually creeps out of its skin, turning it inside out in the 

 effort. 



Order III. 

 Family I. 



CIIELOXIA.(&Y. Xe/Mvrj, a Tortoise.) 

 Testudinida?. (Lat, Tcstudo, a Tortoise. 



Ti:-Tur>o. 







v 



V 



1 i ' r--^. \ ^- ^ - - \ \ \ 



- ' ' 



X'Si-!^- ' 



Graeca (Lat, Greek), the Tortoizr. 



The whole of this order is characterized l.y the complete 

 suit of bony armour with which the animals are protected. 

 The so-called " shell" is in fact a development of various bones, 

 and not a mere horny appendage, like the coverings of the 

 armadillo and mam's. The upper shield is called the " cara- 

 pace," and is united to the under shield, or " plastron," by 

 certain bones, leaving orifices for the protrusion of the head 

 and limbs. Most species are able to withdraw their head and 

 limbs completely within the shell, and in some few the orifices 

 are closed by a kind of hinge joint. The tortoiseshell of com- 

 merce is a series of horny plates that cover the exterior of the 



