Sternum, and Shoulder-Girdle 0/ /Epyoniis. 387 



The Shoulder-Girdle. 



The coraco-scapula (fig. A, p. 386) is typically Strutliious ia 

 form. The scapula {sc.) is fused, and makes an obtuse angle 

 with the broad coraco-precoracoid. This latter has a long 

 sternal border, above which it is narrowed, both its inner 

 and outer borders being concave. Near the middle of the 

 narrowest part is the large supra-coracoid foramen {f.spc.) ; 

 the bar of bone internal to this is probably a remnant of the 

 middle portion of the reduced precoracoid, the upper end of 

 which forms a prominent precoracoid process (|JC.). The 

 outer face of the combined bones is smooth, there being no 

 trace either of the acro-coracoid process or of the coi'aco- 

 scapular protuberance. The curved scapula {sc.) is long 

 and slender ; in the specimen figured the upper end is lost, 

 but other examples show that it was flattened and slightly 

 expanded. The coraco-scapular angle is about 140°. The 

 glenoid cavity {gl.) is small, measuring 15 mm. in its long 

 (vertical) axis, 11 ram. in the short; the coracoid and 

 scapula take equal shares in its composition. 



It will be seen that this coraco-scapula diflers widely from 

 that of Strut hio, in which the precoracoid is a well-defined 

 element; on the other hand, it is much less reduced than in 

 the Dinornithidse, in some of Avhich, indeed, it is entirely 

 wanting. In Rhea the coraco-scapula is also very different, 

 but in Casuarius and Dromceus, particularly the former, 

 the similarity to the fossil is greater, a circumstance that 

 gives support to Milne-Edwards and Grandidier's opinion 

 that Casuarius is a near ally of jEpyornis. Aptenjx is 

 also similar in some respects, but the position of the supra- 

 coracoid foramen is different. 



The dimensions of coraco-scapula are : — 



mm. 



Lenj^th of sternal border (iipprox.) Gi") 



Distance from middle of glenoid cavity to lateral 



sternal angle 00 



Width of opposite supra-coracoid foramen .... 28 



