Yeo 
PROFESSOR OWEN ON THE GENUS DINORNIS. Ld: 
surface. Hence, in a direct front view (fig. 9), little more than the concave fore border 
of the preaxial surface (ac) is seen: while the whole surface is fully in view in the 
under view of the vertebra (fig. 10, ac). It looks almost wholly downward (hemad) in 
Dinornis, not obliquely downward and forward (hemo-preaxiad) as in Struthio’. 
The postaxial surface (fig. 8, pc) much resembles that of the axis vertebra: its trans- 
verse contour is sinuous, a medial convexity dividing two concavities; the aspect is 
more upward than backward; the vertical exceeds the transverse diameter, but in a 
minor degree than do the reverse proportions of the preaxial surface. 
The pleurapophysis (fig. 8, p/) is more prominently marked than in Struthio; a low 
tuberosity represents the diapophysis (fig. 10,d); the interzygapophysial bar (fig. 11, 7) 
has gained breadth; the interzygapophysial foramen (fig. 11, s) is well defined. 
On the under part of the centrum (fig. 10) the transverse preaxial articular concave 
tract is followed by a broad depression beyond. From this begins the medial ridge, which 
expands into the tuberous hypapophysis (hy). This is less produced than in the axis. 
The chief differences from the Ostrich, besides the shorter or broader and deeper 
proportions of the entire vertebra, are seen in the more distinct hypapophysis, the better- 
developed hyperapophyses (fig. 8, hp), and the more distinctly bifid character of the 
neural spine (figs. 9 & 11, ns). 
This spine rises a short way before it divides; a ridge extends from the fore and hind 
margins of each division, and defines the depression (for the insertion of elastic liga- 
ments) in front and behind the undivided base: this, at its summit, is not more than 
FOURTH VERTEBRA (3 natural size). 
Fig. 13. 

Aspects. 
Fig. 12, lateral; 13, hemal. 
one fifth of the antero-posterior extent of the neural platform. (The specimen figured 
is from a higher and larger individual than the articulated skeleton.) 
1 Mivart, loc. cit. p. 394. 
