32 ME. ST. GEOEGE MIVAET ON THE 



from the twenty-fifth or twenty-sixth to the end of the sacro-caudal vertebrse. Its main 

 peculiarities have been already noticed. 



The Pubis (figs. 22 & 26, p). 



This bone may end freely at its distal end ; it may, on the contrary, ankylose distally 

 (as in C. galeatus) with the distal end of the ischium. 



The Ischium (figs. 22 & 26, i). 



The ischium may ankylose distally with the ilium, as in C. galeatus ; it may, on the 

 contrary, end freely, as in C. lennettii, where it extends postaxially beyond the post- 

 axial extremity of the ilium. 



THE VERTEBEAL RIBS (fig. 21). 



These ribs are eleven or twelve in number, according as there are two or three dorso- 

 lumbar vertebreE. The Jirst four are not united to sternal ribs; but to these succeed 

 Jive which are so connected. Finally, there are at least two, more postaxially placed, 

 which end freely at their distal extremities ; and there may be, as in C. ausfralis, three 

 such ribs. 



Uncinate processes may be altogether absent, as in the specimens of C. australis and 

 C. hennettii. There may be, however, three such processes on each side, attached 

 either to the sixth, seventh, and eighth, or to the seventh, eighth, and ninth ribs 

 }espectively. 



The vertebral ribs are flatter and broader than hitherto, and have a different twist. 

 Those postaxiad to the third or fourth rib develop a blunt postaxially developed pro- 

 cess, the process being situated near the proximal end of the shaft of each rib. Each 

 rib (proceeding distadfrom the junction of the tuberculnm with the capitulum) is bent 

 with its convexity preaxiad. More distally its convexity is postaxially directed. The 

 ribs are more like the ribs of Dromwiis than they are like the ribs of any other of the 

 existing Struthionidce ; but they are not so curved, and proceed more directly ventrad. 



THE STERNAL RIBS (fig. 21). 



These bones present no marked differences from those of Dromceus, save that they 

 increase somewhat more gradually in length postaxiad. The first joins the fourth or 

 fifth vertebral rib, and belongs to the twentieth vertebra. The fifth may be twice the 

 length of the first, or it may not reach the sternum. 



