THE INTEESAL SKELETON. 1 89 



its upper end a small concave surface, called the glenoid, into 

 which fits the upper end of the bone of the upper arm or root 

 of the wing. The other division is called the clavicular 

 process, because it articulates with the clavicle. 



The coracoid is not represented by any distinct bone 

 in ourselves, but only by a curved process jutting out from 

 our blade-bone. This has been compared to a crowds beak, 

 whence it was named " coracoid " process, and this has led to 

 the name bestowed on that bone of the bird which corresponds 

 with this process in ourselves. 



The scapula or hlade-hone is another constant element of the 

 limb-girdle, which has received from it the denomination of 

 " scapular " arch. It answers to our " blade-bone," but is very 

 different in shape, being a long, narrow, curved bone flattened 



Fig. 154. 



SiiocLDEK-GiRDLE Or A BiKD (after Parser). 



0, Coracoid (its lower end abuts against the sternum— here removed) ; cl, 

 the clavicles (merrythought); so, the scapula — the rounded glenoid 

 surface, for the head of the humerus, is indicated in the scapula close 

 to the junction of the latter with the coracoid. 



from without inwards, like a small bony sabre passing back- 

 wards over the ribs but quite detached from them. It is, how- 

 ever, rather broad in the Penguins. At its lower end the 

 scapula may be said to bifurcate ; part of it forms a concave 

 glenoid surface which unites with that so named in the coracoid, 

 to f onn the "glenoid cavity "for the reception of the upper 

 arm-bones. The other bifurcation forms a process called the 

 acromial process, which gives attachment to the clavicle. 



The scapula may anchylose with the coracoid, as in the Ostrich. 

 In that and a few other Birds the long axis of the scapula may 

 be nearly in a line with that of the coracoid, but in almost all 

 other existing species they make an acute, right, or only a very 

 slightly obtuse angle. 



