28 ME. ST. GBOEGE IVIIVAIIT ON THE 



The number of vertebrae iu the different species appears to be as follows :- 



Cervical vertebrae 



Cervico-dorsal 



Cervical and cervico-dorsal together . . 



Dorsal 



Dorso-lumbar 



Vertebrae of first four categories together 



Lumbar 



Sacral 



Sacro-caudal 



Caudal 



Saoro-caudal and caudal together 



Total 



ffaleatus. 



15 



4 

 19 



5 



2 

 26 

 10 



3 

 11 



9 

 20 



59 



austrttlis. 



bennettii. 



55 or 56 



THE CERVICAL VERTEBRA. 



ATLAS AND AXIS OF CASSOWAEY (natural size). 

 Fig. 23. Fig. 24. 



Fig. 23. Preaxial view of atlas. Fig. 24. Lateral view of axis. Letters as in figs. 3 & 4,"p. 3. 



The atlas (fig. 23) is very like that of BromcBUs, but has no lateral spicula. The 

 dorsal median notch may become a foramen, as in the specimen figured. 



The axis (fig. 24) is also like that of Dromwus, but a little shorter still. The hyper- 

 apophysis is longer, especially in C. hennettii. 



The third vertebra diflfers from that of Dromceus in that it is shorter axially, and 

 that the styloid rib is much shorter and only about as long as that of JRhea. There 

 may or may not be a perforation in the interzygapophysial ridge. There is a hyper- 

 apophysial keel. 



The fourth vertebra is shorter than that of Dromceus, with a higher neural spine 

 and a shorter and stouter styloid rib. 



