AXIAL SKELETON OF THE STRUTHIONIDA, a 
much longer pre- and postaxially, while its postaxial excavation is very much smaller. 
The central postaxial surface is medianly produced ventrad. The di- and parapophyses 
are as in the twenty-first vertebra of Struthio. The hypapophysis is smaller than in the 
seventeenth vertebra, but extends preaxiad much beyond the preaxial surface of the 
centrum. 
The nineteenth vertebra has the neural spine more pre- and postaxially, but not more 
dorsally, extended than in the eighteenth vertebra. There are no fosse beside it. The 
hypapophysis is very slightly produced. The diapophysial articular surface is placed 
medianly on the transverse process. The posterior zygapophyses do not extend post- 
axially beyond the centrum. 
The twentieth vertebra exhibits the trace of a hypapophysis at each end of the cen- 
trum. It is very like its predecessors, the zyg-, di-, and parapophyses being of about 
the same size and relative position. The neural spine is rather shorter pre- and post- 
axially and a trifle higher. Its postaxial excavation is smaller. 
THE DORSO-LUMBAR VERTEBRA. 
The twenty-first vertebra rather resembles the twenty-fourth of Struthio; but the 
neural spine is much less high, even relatively. There is no trace of a hypapophysis 
postaxially ; but there is a rudiment at the preaxial end of the centrum. The di- and 
parapophysial articular surfaces are about as remote from each other as in the twentieth 
vertebra. When the vertebra is viewed dorsally no radiating lamelle are to be seen, 
thus differing from the twenty-fourth vertebra of Struthio. 
The twenty-second vertebra appears to answer to the twenty-fifth of Struthio, which 
it greatly resembles, except that its neural spine is less high, though it is much longer 
and more slender than in the preceding (twenty-first) vertebra. A vertical ridge 
distinctly divides, medianly, the postaxial neural excavation. 
The twenty-third vertebra differs from its predecessor in that it is shorter pre- and 
postaxially. Its neural spine is higher and more slender, the preaxial surface of its 
centrum is less concaye, and the di- and parapophysial articular surfaces are less remote 
one from another. 
THE LUMBAR VERTEBRZ. 
The twenty-fourth vertebra is the first postdorsal vertebra which has no distinct rib. 
It appears to answer to the twenty-eighth of Struthio, but differs in that its neural spine 
is not higher than its predecessor's, that its transverse processes incline preaxiad instead 
of postaxiad, and that the neural arch is so cancellous and imperfectly ossified. 
