AXIAL SKELETON OF THE STRUTHIONID®. 33 
THE STERNUM. 
STERNUM OF CASSOWARY (j natural size). 
Fig. 27. Fig. 28. 
TX 

Fig. 27. Ventral view. Fig. 28. Lateral view. 
This bone is exceedingly characteristic. It is very long, narrow, and boat-shaped 
compared with that of the other Struthionide. The costal angles are exceedingly short ; 
and between the coracoid-grooves there is a very marked pit, which penetrates deeply 
into the bone and is an exaggeration of that minute notch which exists, in Dromeus, 
upon the median process between the coracoid-grooves. It agrees with the sternum of 
the last-named genus in not having any prominence on the ventral surface, and in 
having neither the ventral surface so convex nor the dorsal surface so concave as are 
these surfaces in Rhea. In all other respects it also agrees with the sternum of Dro- 
meus, except that the costal angles (as above indicated) are so much smaller, and that 
the portion which is postaxial to the pleurosteon is more prolonged. 
VERTEBRAL PARTS AND PROCESSES. 
These skeletal features in Caswarius quite resemble those of Dromeus in those points 
in which the latter have been said to differ from the vertebral parts and processes of 
Rhea, except that the catapophyses continue to the seventeenth vertebra, and that a 
bifurcating hypapophysis appears first at the eighteenth or third cervico-dorsal vertebra, 
as also that the cervical processes may be three in number or may abort altogether. 
VOL. X.—PaRT I. No. 5.—March, 1877. F 
