CHAPTER XXIV 

 SUBPHYLUM VERTEBRATA, CLASS REPTILIA 



Reptiles are cold-blooded, scaly vertebrates, which 

 breathe by means of lungs. The body is never soft and 

 slimy as in amphibians, but covered with a dry skin which 

 conserves the moisture within and permits existence on 

 land without danger of dessication. The representatives 

 of this class are typically terrestrial ; even the marine turtles 

 and sea snakes, which spend their lives in the open ocean, 

 always return to the land to breed. With the exception 

 of the snakes, limbless lizards, and certain other forms in 

 which the legs are somewhat degenerate, reptiles have 

 claws at the tips of the toes. There are four orders of 

 living reptiles and six times as many which existed in the 

 past but are now extinct. The orders of existing reptiles 

 are as follows: 



Order 1. Squamata. Body elongated and covered with small scales, 

 anus slit-like and extending across the body. 



Suborder 1. Sauria. Limbs, eyelids, and external ear opening 

 usually present. Lizards. 



Suborder 2. Serpentes. Limbs, eyelids, and external ear opening 

 absent. Snakes. 



Order 2. Rhynchocephalia. Represented by a single species, 

 Sphenodon punctatum, a, reptile resembling the lizards, but possessing 

 a large eye-like organ in the center of the forehead. This animal is 

 found only in New Zealand. 



Order 3. Testudinata. Body short, broad, and enclosed between 

 two (dorsal and ventral) shields. Turtles, tortoises. 



Order 4. Crocodilia. Body elongate and adapted to aquatic life; 

 limbs present; anus a longitudinal slit. Alligators, caimans, crocodiles. 



Before discussing the different orders, the activities of a 

 little lizard which inhabits the Eastern United States will 

 be considered in detail. 



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