SKELETON OF UPPER LIMB. 



155 



the anterior border, as in the Dolphin. There may be a 

 second spine behind the normal one, as is the case in the 

 Armadillos. 



An acromion process is the ordinary Mammalian termi- 

 nation to the scapular spine, but this may be utterly wanting, 

 as in the Hyrax and the Giraffe. It may not only be large, 

 but give off a distinct post-axially directed process, termed 

 the metacromion, as in the Hare, Elephant, and Shrew, the 

 acromion in the latter animal appearing to bifurcate. 



Ff 



FIG. 129 SIDE VIEW OF RIGHT SHOULDER GIRDLE OF YOUNG ECHIDNA 

 (Echidna hystrix}. 



!>s, supra -scapular epiphysis ; ssf, sub-scapular fossa ; pf, post-scapular fossa ; cb, 

 coracoid border ; gb t glenoid border ; s, spine ; a, acrcmion ; ess, coraco- 

 scapular suture ; gc, glenoid cavity ; c, coracoid ; ec, epicoracoid ; cl, clavicle ; 

 ic, inter-clavicle ; ps, pre -sternum, or manubrium. 



(From Flowers "Osteology."} 



The acromion may join the coracoid process, and thus form 

 a bony loop, as in the Two-toed Sloth and in Birds the bony 

 connexion answering to the ligament which connects the 

 processes in man. 



A distinct acromion process may be developed where 

 there is no clavicle, as is the case in the Dolphin. It may be 

 very long and present an articular surface for the humerus, 

 as is sometimes the case in the Armadillos. 



The articulation which takes place between the acromion 



