AXIAL SKELETON OF THE STRUTHIONID#. 15 
This bone is narrower in proportion to its pre- and postaxial length than in Struthio. 
The coracoid grooves are not nearly so approximated ; and their dorsal margins project 
but little, if at all, preaxiad beyond their ventral margins. The costal angles are narrower 
in proportion to their length. There is no median preaxial projection. The lateral 
xiphoid processes are small, and project but little postaxiad, leaving but a moderate 
notch (and no median xiphoid process) between them. The sides of the sternum are 
less concave. The median ventral prominence (fig. 10, f') is not flattened. Each pleu- 
rosteon has but three articular surfaces; and each of these has a deep excavation 
postaxial to it. The ventral facet of each articular surface exceeds the dorsal one in 
size; but they are most nearly equal in the third articular surface. 
VERTEBRAL PARTS AND PROCESSES. 
The centra resemble generally those of Struthio, except as to which are the ones 
which became ankylosed. These parts may all but abort altogether, as in the anterior 
caudal vertebre. 
The neural lamine do not show such signs of shifting as in the lumbar vertebre of 
Struthio. The neural arches may entirely abort, while the centra still exist in an im- 
perfect manner, as in the anterior caudal vertebre. The substance of the lamine may 
be so cellular as to be most extremely imperfect in development, as in the lumbar and 
sacral vertebre. Diapophyses may be quite absent, if not blended with the spinous 
processes, as in the last six presacral vertebre. 
The neural spines are most expanded, pre- and postaxially, in the dorsal vertebre. 
They may be laterally bifid, as in the third cervico-dorsal vertebra. The zygapophyses 
are developed as in Struthio; and the metapophyses offer no great differences. 
Hyperapophyses ave only conspicuous in the second, third, fourth, and fifth vertebre. 
Diapophyses and parapophyses are occasionally absent where they are present in 
Struthio, notably in the last five lumbar vertebra. No such processes abut against the 
ischium. 
The pleurapophyses of the cervical region differ greatly from those of Struthio by 
their shortness and non-styloid form. 
Hypapophyses are nowhere distinctly paired. 
Catapophyses are found preaxiad to the fifteenth vertebra. 
The vertebra are raised above (i. ¢. dorsally to) the acetabula. 
The vertebral ribs have a different twist from that existing in Struthio. 
The uncinate processes do not seem to be more than three in number. 


