TUPAIID^. 121 



The meso-sternmn consists of five nearly equally large and broad rod-like pieces, 

 the 2nd, 3rd, 4th, and 5th showing more or less distinct traces of a median groove, 

 which is most marked on the 4th. The xiphi-sternum is a long rod-like bone the 

 length of two and one-half of the meso-stemal elements, and is slightly dilated at its 

 free end. The cartilage of the ninth rib runs close up to the last segment of the 

 meso-stemum along the cartilage of the 8th rib, but stops short of being connected 

 to the sternum. 



The outhne of the scapula is a figure resembling the half of a moderately 

 rotund oval, divided unequally by the meso-scapula or spine, which is extended nearly 

 as far outwards as the breadth of the middle portion of the post-scapular plate. It 

 rises in a gentle slope from the supra-scapular border as far as the upper third of the 

 distance between the last-mentioned border and the tip of the acromion process. 

 Anterior to that it forms a sharp, outwardly directed ridge parallel with the post- 

 and pre-scapular surfaces, less in extent than one-fourth of the before-defined area. 

 It is then bent slightly backwards, the margin of the ridge being directed backwards 

 and sHghtly upwards, giving rise to a flattened convex sm^face roofing in the sub- 

 scapular fossa and continuous with the acromion process. Posteriorly, the inferior 

 hinder margin of this flattened surface forms a weU-deflned angle, and the 

 acromion joins the meso-scapula by a slightly constricted sm'face common to 

 both. 



The acromion is moderately broad, and is directed more forwards than down- 

 wards, being bent also inwards over the coracoid. The coracoid is a small hook 

 of bone directed forwards, downwards, and backwards, till its tip is on a line 

 with the anterior border of the glenoid facet. The glenoid facet is cup-shaped, 

 but a pointed articular surface from its anterior margin is prolonged on to 

 the base, as it were, of the coracoid process. The sub-scapular fossa presents 

 nothing worthy of note. The coracoid border is contracted at its base above its 

 process ; it then bends forwards, upwards, and backwards in a moderate sweep 

 to the superior extremity of the meso-scapula, beyond which it is continued 

 upwards and backwards as the supra-scapular border. The margin is sHghtly 

 thickened. 



The pre-scapular plate is marked by a long, shallow depression, almost consti- 

 tuting a groove, which commences at the inferior anterior extremity of the 

 meso-scapula, and is directed upwards and slightly outwards, terminating exter- 

 nally at the upper third of its border. The post-scapular plate has its glenoid 

 border turned slightly forwards, and a little above its upper half it bifurcates 

 to the posterior supra-scapular angle, enclosing a narrow concave surface. 

 From the outward and sKghtly forward prolongation of the border, the post- 

 scapular plate is concave along the border. The inner aspect of the two plates 

 presents two ridges and a median groove or hollow, the latter corresponding to 

 the course of the meso-scapula; the anterior of the ridges, to the groove on 

 the external surface of the pre-scaj)ula ; and the posterior, to the Hne marking 



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