20 THE ARTISTIC ANATOMY OF ANIMALS 



THE ANTERIOR LIMBS^ 



The anterior limbs, homologous to the upper limbs in 

 man, are formed, as in the latter, of four segments : the 

 shoulder, the arm, the forearm, and the hand. These limbs, 

 considered in the vertebral series, present themselves under 

 very different aspects, which are determined by the functions 

 they are called upon to perform. 



They constitute the forepaw in terrestrial mammals ; in 

 aerial vertebrates they form wings ; in aqueous mammals 

 they act as paddles. In whatever series we study them, 



Fig. 8. — Anterior LiMr; of the Bat : Left Side, Anterior Surface. 



I, Clavicle ; 2, scapula ; 3, humerus ; 4, radius ; 5, cubitus ; 6, carpus ; 

 7, thumb ; 8, metacarpus ; 9, phalanges. 



we can readily find the relationship of the different parts ; 

 it is very easy to recognise the same bones in the upper limbs 

 of the human being, the wings of the bat (Fig. 8) and of 

 birds (Fig. 21), and in the anterior paddles of the seal (Fig. 9) 

 and of the dolphin. 



In quadrupeds, the shoulder and arm are hidden, the 

 latter more or less completely, in the muscular mass which 

 binds it to the lateral wall of the trunk ; so that the anterior 

 limbs only present ; free from the trunk : the elbow, forearm, 

 and hand. 



The Shoulder 



In some vertebrates, the shoulder is formed of two bones — 

 the scapula and clavicle ; in others of only one bone — the 

 scapula ; the clavicle in this case does not exist. 



* Consult Fii^s. 21, ^t,, 34, 38, 39, 46. 



