112 



BRANCH VERTEBRATA. 



CLASS BEPTILIA (rep til'I a). 



The members of this class have the body scaled, and 

 the toes, when present, provided with claws. The de- 

 velopment lacks the metamorphosis so characteristic of 

 the previous class, the young generally hatching from a 

 large egg, which is surrounded by a tough membrane, if 

 not by a calcareous shell. A few forms are ovovivipa- 

 rous lo vo vi vip'a rus), the young being born. The class 

 includes animals having the most diverse habits, and con- 

 sequently, those possessing great variety as to form and 

 general structure. All are air-breathers. 



ORDER OPHIDIA (o fid'i a). 



The Ophidians are without feet, and though the pelvic 

 arch may in some forms bear rudimentary appendages, 



all trace of pecto- 

 ral limbs has dis- 

 appeared. They 

 are, however, able 

 to progress with 

 great rapidity by 

 a wriggling mo- 

 tion of the body, 

 together with the 

 pushing of the 

 large ventral 

 scales, each of 

 which is fastened 



Skeleton of a Serpent. 



to a single pair of 



ribs. The jaw-bones are but loosely attached together, 

 and to the skull, and allow great, though limited, dis- 

 tensibility of the mouth. The tongue is bifid (bi'fid), and 



FIG. 193. 



