361 



base of the coracoid (h). The tubercular ridge (i, figs. 3, 6) for the ' triceps longus ' 

 muscle is well marked ; it begins near the lower usually sharp border of the glenoid 

 cavity ; and a roughness may be traced from it along one third of the hind border (a). 

 The acromion (/,/') extending beyond the glenoid cavity, curves gently toward the 

 coracoid. This element, or process (h), is short, thick, and inclines obliquely inward, or 

 toward the subscapular surface or aspect (figs. 2, 5). This surface is undulate. A lon- 

 gitudinal channel, parallel with the origin of the spine, is bounded by longitudinal con- 

 vexities, the upper one subsiding to a concavity at the antero-superior angle of the 

 quadrilateral, the lower one to a concavity along the hind border. The short straight 

 'base' (d) or 'vertebral border' of the scapula is thicker than either of the other borders 

 or ' costee,' and is thickest at the angles where it joins them, and which are rounded off". 

 The spine takes a more oblique course to the neck in Phascolomys platyrhinus (fig. 4) 

 than in Phascolomys latifrons (fig. 1) ; the body of the scapula is broader in proportion 

 to its length, and the glenoid cavity is narrower in proportion to its length in Phase, 

 platyrhinus. In Phase, latifrons I have noted a variety in which the antero-inferior 

 angle of the quadrilateral was more produced and the cervical emargination shorter and 

 deeper ; but usually the form of this part is nearly the same in both species. The hind 

 angle of the base is produced backward in Phase, latifrons (figs. 1 & 2, a) ; not so in 

 Phase, platyrhinus. The subscapular surface (figs. 2, 5, k) near the postsuperior angle 

 (b), for the attachment of part of the ' serratus magnus,' is defined by a stronger ridge 

 in Phascolomys latifrons (fig. 2) than in Phascolomys platyrhinus (fig. 5). 

 I append the following dimensions : — 



The head of the humerus (PI. CI. figs. 1-4), especially the articular part (a), shows 

 a difference of proportion corresponding with the indication afforded by the glenoid 

 cavity of the scapula ; its antero-posterior or short diameter is greater, in comparison 

 with its transverse or long diameter, in Phascolomys latifrons (ib. fig. 2, a), where it 

 extends lower down and is narrower at its termination at the back of the humerus, than 

 in Phase, platyrhinus (ib. fig. 4, a). The entire bone is stronger, broader in proportion 

 to its length, in Phase, latifrons (ib. figs. 1 & 2). 



In both species the proximal tuberosities are well developed, but they are relatively 



1 PL C. figs. 1-3. 2 From a larger individual than the subject of PL C. figs 4-6. 



' In a second specimen it was 2 inches 2 lines. 



Extreme length of the blade-bone 5 



Length of hind border (' external or axillary costa ') . . . 4 



Length of front border (' superior costa ') 3 



Length of base (' vertebral costa ') 1 



From lower (cervical) angle of front border to end of coracoid 1 



Breadth of the middle of the scapula 1 



Ph .platyrhinus 2 . 



