146 



ZOOLOGY. 



are five bones, reckoned numerically, from the inner to the 

 outer side of the foot ; and in the region of the toes, there 

 are for the great toe, two phalanges, and for the others three; 

 besides these, as in the hand, there are two sesamoid bones, 

 constant and regular, developed in the tendon of the short 

 flexor below the ball of the great toe. 



In man the great toe cannot be opposed to the others ; the 

 second toe is the longest in all well-formed human feet. The 

 tarsal and metatarsai bones form a strong arch towards the 

 inner and lower surface of the feet, protecting the vessels, 

 nerves, and tendons passing from the foot to the leg, and the 

 opposite. The short flexors of the toes are placed in the sole 

 of the foot; the tendo-Achilles, the strong tendon through 

 which the extensor muscles act on the foot in walking, is 

 attached to the tuberosity of the calcarieum. The size of the 

 peroneal muscles is a peculiarity in the human leg. The 

 same remark applies to the gastrocnemii muscles. 



Of the Attitudes and of Locomotion, 



283. All mammals, birds, reptiles, and fishes have a 

 skeleton formed on the same plan as in man. It gives to 

 the body its general form, regulates its development and 

 movements. 



284. Station or Standing. With the exception of 

 serpents, most animals rest on the soil by means of limbs or 



extremities. They 



r stand by means of 



the action of the ex- 

 tensor muscles : and 

 thus standing for 

 a long time erect 

 becomes more fa- 

 tiguing than walk- 

 ing, for in this the 

 . flexorsand extensors 

 are used alternately. 

 285. But the 

 body must also be 

 in equilibria, or 

 balanced on its base of sustentation ; and the point around 

 which all its movements are performed is called the centre of 

 gravity. Now, to support the centre of gravity, it is neces- 



Fig. 97. 



