CHAPTER XIX. 



THE HIND FOOT OR PHS. 



THE terminal segment of the hind limb is the foot or pes. 

 Its skeleton presents in many particulars a close re- 

 semblance to that of the manus, being divisible into three 

 parts : (i) a gro'ip of short, more or less rounded or square- 

 shaped bones, constituting the tarsus ; (2) a series of 

 long bones placed side by side, forming the metatarsus ; 

 and (3) the phalanges of the digits or toes (see Fig. 

 122, p. 341). 



The metatarsal bones never exceed five in number, and 

 the phalanges follow the same numerical rule as in the 

 manus, never exceeding three in each digit. Moreover, the 

 first digit (counting from the tibial side), or hallitx, resem- 

 bles the pullex of the hand in always having one segment 

 less than the other digits. If one toe only is absent, it is 

 the first or hallux. Unlike those of the manus, any of the 

 five toes of the foot may be absent or at least rudimentary ; 

 the fourth and fifth are best developed in Macropus, the 

 third and fourth in J'fcora, the fourth alone in Choeropus, and 

 the third alone in Eqniis. 



The bones of the tarsus in many of the lower Vertebrata 

 closely resemble both in number and arrangement those of 



z 2 



