XII 



PHYLUM CHORDATA 



409 



in the ordinary position, is directed backwards and down- 

 wards from the shoulder joint ; a fore-arm, directed down- 

 wards and forwards from the elbow ; and a hand, ending in 

 four short tapering digits, directed forwards. The hind-limb 

 is of great size ; in the usual squatting posture the thigh is 

 directed downwards, outwards, and forwards from the thigh- 

 joint, the shank inwards, backwards, and upwards from the 



Fie. 246. — Rana temporaria. (From Mivart.) 



knee. The foot consists of two parts, — a tarsal region directed 

 downwards from the heel-joint, and five long, slender digits 

 united by thin folds of skin or webs. Thus the limbs are 

 placed in such a way that the elbow and knee face one 

 another, and the first digit — that of the hand probably rep- 

 resenting the second or index-finger, that of the foot, the 



