236 PROFESSOR OWEN ON THE GENUS DINORNIS. 
process ascending to the mastoid. Of this bone the production descending outside of 
the above articular process gives strength to the joint. 
The mandible (PI. LII. figs. 5, 6, 7), 4 inches 9 lines in length, repeats, with slight 
specific modifications, the characters of the bone described and figured in the volumes 
of the Zoological ‘Transactions’ already cited. There is no closer approach in the 
present small species of Dinornis to the cranial characters of Apterya than in any of 
the larger kinds of Moas. The entire osteology of D. parvus helps greatly to exemplify 
the well-defined character of the group of wingless birds of New Zealand to which the 
generic term Dinornis is applied. 
§ 3. Vertebre. 
In the best-preserved, or least incomplete, skeletons of Dinornis already described, 
the “dorsal series” of vertebra, defined as commencing by the first or foremost 
“retaining its pleurapophyses as movable elements,” was preceded by not more than 
fifteen vertebra, showing no costal articular cup; and these accordingly were reckoned 
as “cervicals.” But the slight degree of difference as to size or structure in the mid 
extent of this series would allow of easy coarticulation of such vertebre without 
appreciable indication of one or even more being absent. 
From the circumstances under which the present skeleton was found, and the 
singular care in the collection of its several parts, it shows a number of cervicals, as above 
defined, not fewer than twenty-one (Pl. LVIII. 21). 
To these succeed six rib-bearing vertebre (ib. ib. D) not confluent with the sacrum, 
the last forming, in the present species of Dinornis, the twenty-seventh vertebra, counting 
from the occiput. Eighteen following vertebre are confluent with each other and with the 
contiguous pelvic elements (Pl. LIV. 1-18), including those which in most Mammals and 
Reptiles would be reckoned as posterior dorsals, lumbars, and anterior caudals. Of 
free caudal vertebre there are eleven (ib. figs. 2,3) in the present skeleton, of which 
the two hindmost have coalesced. Thus there are not fewer than fifty-six vertebre in 
the ‘axial skeleton’ of Dinornis parvus. 
The first or foremost vertebra consists in this, as in other Moas and birds generally, 
of the hypapophysis (Pl. LI. figs. 2-4, hy) and neural arch (ib. ), which have 
coalesced to form the so-called ‘atlas.’ The second vertebra (ib. figs. 5-9) includes, 
with the hypapophysis (Ay), the centrum of the first vertebra (c'), as well as its own (c’), 
and the neural arch (m), thus constituting the so-called ‘ axis’ or ‘ vertebra dentata.’ 
In Part XXI. (Dinornis) three views (upper, under, and front) are given of the 
atlas of Din. mazimus'’. The extreme length of this vertebra is 26 millim., the greatest 
breadth is 32 millim., the height is 35 millim., the transverse diameter of the cavity 
for the occipital condyle is 15 millim. 
In Part IX. (Dinornis, pl. liii. figs. 4, 5, 6) three views (front, back, and side) are 
* Trans. Zool. Soc. vol. x. (1875), p. 148, figs. 1, 2, 3. ? Tbid. vol. v. 1864, p. 357. 
