AXIAL SKELETON OE THE STKUTHIONLD^. 23 



than in the preceding genera ; but the vertebral column is seen behind it as in Struthio. 

 The preaxial margin of the ilium is still more concave than in Rhea. 



When the pelvis is viewed dorsally the supraacetabular processes nearly hide the 

 antitrochanteric processes. Eight serial openings are visible in the middle of the post- 

 acetabular part of the ilium. The surfaces between these apertures are composed of 

 the flattened summits of the sacro-caudal neural spines interposed between the more 

 postaxial parts of the two ilia. The pubis appears, thus viewed, very slightly, if at all, 

 concave inwards ; but the ischium is slightly concave outwards. The posterior ends of 

 the ilia diverge as in Struthio, thus differing from Rhea. 



Viewed ventrally, this complex bone presents five pieces proceeding postaxially as in 



PELVIS or EMU (I natural size). 

 Fig. 18. 



Ventral view. 

 at, antitrochauteric process; i, ischium ; il, ilium ; Ip, ilio-pectineal process ; p, pubis ; sp, interobturator process. 



Struthio ; but, as in Rhea, the ilio-pectineal eminences are smaller than in the African 

 genus; but the ischia are more visible medianly, thus differing from Rhea. The pre- 

 acetabular part of the pelvis is relatively greater than in either of the other genera ; 

 and the number of transverse processes there is greater. Also the transverse processes 

 are broader generally, and fill up the middle of the more postaxial half of the ventral 

 sui-face of the pelvis with almost continuous ossifications. The sacral transverse pro- 

 cesses are much smaller than in Struthio, but are much better ossified than those of 

 Rhea, as are also the more postaxial transverse processes. The fossa left between the 

 one (34th) or two lumbo-sacral vertebrae and the adjacent acetabulum on each side is 

 very small and inconspicuous. 



The Ilium (figs. 13 & 18, il). 

 The ilium extends over the vertebrae from the twenty-sixth to the forty-fifth inclusive. 

 It is like that of Rhea, except in the points already noticed, and that it is much less 

 flattened against the postacetabular vertebrae than in Rhea and less so than in Struthio. 



