336 THE CORRESPONDENCE BETWEEN THE [chap. 



In every Mammal both scapula and ilium may be re- 

 solved into bars or rods of three-sided or prismatic form. 

 The two extremities of each bar are placed, as regards the 

 general position of the trunk, dorsally and ventrally. The 

 dorsal or upper extremity is capped by the suprascapular 

 epiphysis in the shoulder girdle, and by the corresponding 

 supra-iliac epiphysis in the pelvic girdle. The ventral 

 or inferior extremity enters into the formation of the 

 glenoid or the acetabular articular cavity, as the case 

 may be, and joins the coracoid or the ischial element of 

 the girdle. 



The bar, supposed to be in a nearly vertical position, has 

 three surfaces and three borders. In what may be, at least 

 theoretically, considered their primary position, the surfaces 

 of each bar are — (i) Inner or vertebral, turned towards the 

 vertebral column; (2) Preaxial, corresponding to the preaxial 

 hne of the limb (Fig. 125, k pf^ b is); (3) Postaxial, cor- 

 responding to the postaxial line of the limb (a ssf, b gs). The 

 borders are — (i) External, in a line with the middle of the 

 dorsal surface of the limb, and terminating below at the 

 upper margin of the glenoid or acetabular cavity (a gb^ b aly) ; 

 (2) antero-internal, terniinating below in the acromion or 

 in the pubis (a j-, b ph) ; (3) postero-internal, terminating 

 below in the coracoid, or the ischium, as the case may be 

 (a cb, B ib). 



The correspondence between these parts of the scapula 

 and ilium will be better understood by placing them in 

 a tabular form, the middle column showing the names 

 expressed in the generalized or ideal condition applicable 

 to both in their primitive condition, and the column at each 

 side giving the special terms applied to each part in its 

 variously modified forms. 



