PROFESSOR OWEN ON THE GENUS DINORNIS. 159 
a corresponding but greater one marks the opposite or neural surface, one process (hy, 
fig. 18) descending, the other (ns) ascending. The neural spine gives off a pair of low 
tuberosities, one on each side, near its summit: from each there is continued the usual 
FIFTEENTH VERTEBRA (4 nat. size). 

Aspects. 
Fig. 18, lateral; 19, hemal (ventral), 
ridge curving back to the hyperapophysis (fig. 18, ip), which still overtops the post- 
zygapophysis, pz. 
A mere rudiment of the interzygapophysial band now remains, but behind it is a 
small foramen leading to the cancelli of the neurapophysis; a corresponding foramen 
is noticed in Struthio!. The pneumatic foramen is, as usual, beneath the base of the 
diapophysis, which process shows its tuberous outstanding metapophysis (fig. 18, m), 
well marked above the pleurapophysial band, pl. This, as in the seventeenth (last 
cervical) vertebra in Struthio, is short antero-posteriorly, and each margin is concave, 
with a blunt production of its hinder and lower angle still representing the cervical 
riblet. Each vertebrarterial canal (figs. 20, 21, v), asin Struthio, exceeds the neural 
canal in capacity. 
If the transverse expansion of the fore part of the centrum be reckoned as due to the 
1 Mivart, loe, cit. p. 409, 
