CLASS KEPTILTA: ORDER LORICATA. 169 



Fig. 283. 



Turtle's nest in the sand. 



ORDER LORICATA. 



General Characteristics. The Mail-clad reptiles are 

 found in the swamps and rivers of warm regions. Bony 

 plates set in the leathery hide form a bullet-proof cuirass. 

 The lower jaw is composed of six bones of varying length, 

 put. together like the steel plates in carriage-springs. This 

 secures the elasticity required by its inconceivably-quick 



Alligator's lower jaw. 



snapping bite. To get an enormously-large gape, the lower 

 jaw is articulated to the back part of the skull, giving the 

 appearance of motion to the upper jaw independent of the 

 cranium. The conical, deciduous teeth are constantly re- 

 newed. The nostrils at the end of the snout communicate 

 with the pharynx behind cartilaginous plates, which prevent 

 the water from running down the throat, and enable the 

 animal to breathe while it has its mouth open in drowning 

 its prey. The nose and ears are also provided with valves to 

 keep out the water. The tail articulates with the backbone 

 by a ball-and-socket joint, so that with a quick lateral mo- 



