238 BRANCH CHORDATA 



Reptiles always breathe by lungs. "The air is drawn into 

 the lungs of snakes, lizards, and crocodiles by the play of the 

 ribs."^ 



The nervous system is somewhat more highly developed than 

 in the amphibians. There is a middle and an inner ear. The 

 eye has an upper and a lower movable eyelid and also a nicti- 

 tating membrane (Fig. 196). True nostrils and salivary glands 

 appear first among the reptiles. 



Reptiles are oviparous, ovoviviparous, or viviparous. There 

 is no metamorphosis. 



In ecdysis the skin may be cast in one piece, as in all snakes 

 save sea-snakes and in most lizards; in strips, as in some lizards; 

 in little pieces, as in the western horned toads; or in flakes, as in 

 the geckos. Some tortoises shed the whole outer layer of epi- 

 dermal shields periodically. 



Gadow briefly defines Reptilia as "monocondylia with a scaly 

 skin." 



Reptiles live longer than most warm-blooded animals. A 

 turtle in the Zoological Park, New York, says Ditmars, is esti- 

 mated to be over three hundred and fifty years old. 



ORDER I. RHYNCHOCEPHALIA 



Rhynchocephalia is represented by Sphen'don ptmcta'tum 

 {Hatte'ria) of New Zealand. It is a lizard-like, four-limbed, 

 pentadactyle, nocturnal, carnivorous reptile | meter in length. 

 "It is the sole remnant of an order long extinct. It is literally 

 a ghost of the past, the oldest surviving type of reptile." — 

 Ditmars. 



Its color is dark olive green, with small white or yellowish 

 specks on the sides. Its length is from 15 to 30 inches, while 

 fossil forms were sometimes 6 feet long. A row of spines extends 

 along the back. Its means of defense are biting and scratching. 

 It burrows. It lays about ten hard-shelled white eggs in the 

 sand. Gadow has "come to the conclusion that they are dull, 

 not companionable creatures." Their sound is a grunt or croak. 



For an interesting description of this living fossil read Gadow, 

 "Amphibia and Reptiles," pp. 294-300. Look at the picture of 

 the skeleton and state the branch, class, and ordinal character- 

 istics you see, 



' Dodge. 



