THE ANIMAL MACHINE 13 



loin, the sacral or coupling, and the coccygeal or tail. 

 The ribs spring from the thoracic vertebrae and are 

 attached, the anterior directly, the posterior indirectly, 

 to the sternum or breast bone, which constitutes the 

 region of the brisket in ruminants. The ribs inclose the 

 thorax or chest cavity and a part of the abdominal cavity. 

 Superiorly upright spines are developed from the thoracic 

 vertebrae, which give form to the withers or chine 

 (Fig. 6). 



12. The foreleg. — The legs or extremities consist of 

 columns, too, each divided into regions. The fore leg is 

 composed of a scapula or shoulder blade, humerus or arm, 

 radius and ulna or forearm, carpus or knee, metacarpus 

 or cannon, the first and second phalanges which constitute 

 the pastern, the latter more particularly the coronet, and 

 the pedal, coffin, or foot-bone. 



13. The hind leg. — The hind leg includes the pelvis 

 or hip, by means of which the coupling between the spinal 

 column and the hind leg. is made and which also forms the 

 pelvic girdle inclosing the pelvic cavity through which the 

 fcetus has to pass in the female, the femur or thigh, 

 the patella or knee, the tibia and fibula or lower thigh, 

 the tarsus or hock, the metatarsus or cannon, the re- 

 mainder of the leg being a duplication of the anterior 

 extremity. 



14. The foot. — The region below the knees and hocks 

 is anatomically considered as the foot proper, the appro- 

 priateness of which is shown by a study of the analogous 

 parts in the biped and the intervening stages in the rabbit 

 and the cat. 



15. The joints. — The legs constitute supportmg col- 

 umns while at rest, but the extremities of the individual 

 bones, opposed to each other in the columns, are furnished 



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