175 



gives attachment to a ligament passing to the hinder border of 

 the acromion. Between this process (p) and the glenoid cavity 

 is the neck. 



The coracoid border terminates in a very small coracoid process 

 (fig. 3b c) which blends with the margin of the glenoid fossa, and in 

 fact may be said to share in the formation of the articular sur- 

 face. It gives attachment to a coraco-acromial ligament. The 

 subscapular fossa is slightly concave from the glenoid to the 

 coracoid border. 



The glenoid surface is subtriangular in shape, and concave. 



A considerably elongated mesoscapular segment is connected 

 with the acromial process, and continues this forwards and in- 

 wards (figs. 1, 3b m.s.s.). To its bevelled end is attached the clavicle. 



The clavicle (figs. 1, 3b cl.) is a very slender, curved, styliform 

 bone, which ends in an enlarged sternal extremity. This, how- 

 ever, does not reach the sternum, but it is continued onwards as 

 a ligament about half a centimetre in length, which is attached 

 to the anterior border of the keel of the manubrium sterni. 



THE ARM AND FOREARM. 



(PI. YIII.. tigs. 2— 5a). 



The humerus (figs. 2 — 3b) is a stout, strong bone, with its inferior 

 extremity very much widened from the great extension inwards 

 of the internal epicondyle. The head is rounded, and there are 

 well-marked external and internal tuberosities. The ectocondylar 

 and deltoid ridges are well-marked, and the musculospiral groove 

 wide and deep. No supratrochlear or supracondylar foramen. 

 The trochlear surface is almost comj)letely divided by a deep notch 

 into two portions, of which that for the radius is the larger. 

 The internal epicondyle terminates in a hook-like process. 



The ulna (tigs. 4, 5) is remarkable for its long and much in- 

 curved olecranon process, the length of the process being nearly 

 as great as that of the shaft. The shaft, wide above, from before 

 backwards, and grooved on its hinder surface, tapers to a slender 

 rod below, wliich curves a little outwards and backwards, and 

 has a small blunt styloid process. In the natural position, the 

 ulna, lies behind the radius for its whole length. The surface of 

 articulation for the humerus is deeply concave from abore down- 

 wards, and its inferior lip constitutes a coronoid process. The 

 superior lip is also prominent. Externally is a concave surface, 

 for the head of the radius, whicli is bounded superiorly by a 

 prominent lip. 



The radius is about half the length of the ulna, including 

 the olecranon. Its head is considerably expanded, and so, 

 also, is its inferior extremity, from which proceeds a styloid pro- 

 cess. Its articulation with the ulna and with the humerus has 



