CH. VIII] FROGS, TOADS, AND NEWTS 249 



The tympanic membrane of the ear is situated a short 

 distance behind the eye in the black patch already referred 

 to: its margin is marked by an almost circular ring of 

 cartilage which can be detected through the skin; the 

 disc thus circumscribed is slightly concave and has attached 

 to its centre internally the rod-like columella establishing 

 connexion with the internal ear. 



There is no neck. The trunk, when the animal is 

 squatting, presents a very decided dorsal hump about 

 halfway along its length. This projection is caused by 

 the long hip-bones (ilia) which are at this point attached 

 to the last (ninth or sacral) vertebra, and thus transfer 

 the movements of the hind legs to the trunk and entire 

 body. 



The disparity of front and hind limbs is very striking. 

 The former are short and of quite secondary importance 

 in locomotion either on land or in the water: they are used 

 in slow or scrambling movements through herbage and 

 also to raise the fore-part of the body and head and impart 

 an upward inclination to the animal when it jumps, and 

 thereby increase its trajectory. In alighting the front feet 

 are the first to reach the ground, and act as spring buffers 

 for the protection of the head and body against the shock 

 of impact. When at rest the animal keeps the elbows 

 turned outward and the four digits of each front foot 

 turned in towards the middle line. 



The hind legs are relatively enormous, being more than 

 twice as long as the front legs. The thigh and shin together 

 are about double the length of their serial homologues the 

 upper arm and fore-arm, but the ankle and foot are between 



