24 me". ST. GEORGE MIVART ON THE 



The Pubis (figs. 13 & lS,p). 



This bone does not join the ischium, but ends freely distad, as it does in the j'oung 

 Bhea. It projects least postaxiad of the three pelvic bones. 



The Ischium (figs. 13 & 18, i). 



This bone also ends freely distad, as it does in the young Bhea. Its ridges are con- 

 ditioned as in Struthio. It expands slightly distad in both directions, as a hammer. It 

 is the pelvic bone which extends furthest postaxially, yet very little beyond the ilium. 



THE VERTEBRAL RIBS (fig. 12). 



There are nine vertebral ribs, the last of which becomes ankylosed with the pelvis 

 in the adult. The "fourth, fifth, sixth, and seventh vertebral ribs join sternal ones. 



The_^;'s^ rib is much longer than broad. It remains unankylosed in the adult, and 

 is attached to the nineteenth vertebra. 



The second rib is broader than in Rhea or Struthio. It has a convexity on its post- 

 axial margin, a little below the tuberculum. 



The third rib is broader and more convex than in Rhea or Struthio. The tubercular 

 articular surface is a good deal larger than in the second rib. The postaxial margin is 

 convex dorsally, and ventrally concave. 



The fourth rib is like that of Rhea; but the uncinate process may be absent or pre- 

 sent, when it is short and broad. 



The fifth rib is very like its predecessor, but is slightly shorter and more curved, and 

 the angle formed by the capitulum and tuberculum is rather more obtuse. There may 

 or may not be a short, thick uncinate process. 



The sixth is like that of Rhea, and is shorter and more curved than its predecessor. 

 There is no uncinate process. 



The seventh rib difiers from that of Rhea in that it is not free distally. It is rather 

 slighter, shorter, and more curved than its serial predecessor, while its diapophysial 

 surface is quite as large. Its preaxial prominence is not more marked. 



The eighth rib is but very slightly, if at all, longer than the second rib. The pre- 

 axial convexity does not project much ; but the ridge which crosses that part where the 

 head and tubercle diverge is very strong. 



The ninth rib, which may be articulated with or ankylosed to its vertebra, is shorter, 

 more slender, and less curved than its predecessor. It is more curved than in Struthio, 

 and less so than in Rhea. 



THE STERNAL RIBS (fig. 12). 



Of these there are four ; and they increase in length postaxiad with very much greater 

 rapidity than in Rhea, the third being twice the length of the first. 



