236 PEOFESSOK 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 Apteryx than in any of 

 the larger kinds of Moas. The entire osteology oi B. 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. Vertebrae. 



In the best-preserved, or least incomplete, skeletons of Dinornis already described, 

 the " dorsal series " of vertebrae, defined as commencing by the first or foremost 

 " retaining its pleurapophyses as movable elements," was preceded by not more than 

 fifteen vertebrae, 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 vertebrae 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 (PI. LVIII. 21). 



To these succeed six rib-bearing vertebrae (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 vertebrae are confluent with each other and with the 

 contiguous pelvic elements (PI. LIV. 1-I8), including those which in most Mammals and 

 Reptiles would be reckoned as posterior dorsals, lumbars, and anterior caudals. Of 

 free caudal vertebrae 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 vertebrae 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 (PI. LI. figs. 2-4, hy) and neural arch (ib. n), which have 

 coalesced to form the so-called ' atlas.' The second vertebra (ib. figs. 5-9) includes, 

 with the hypapophysis {hy), the centrum of the first vertebra (c'), as well as its own (c^), 

 and the neural arch (w), thus constituting the so-called ' axis ' or ' vertebra dentata.' 



In Part XXI. [Dinornis) three views (upper, under, and front) are given of the 

 atlas oi Din. maximus^. 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, pi. liii. figs. 4, 5, 6 ^) three views (front, back, and side) are 

 ' Trans. Zool. Soo. vol. x. (1875), p. 1-iS, figs. 1, 2, 3. ' Ibid. vol. v. 1864, p. 357. 



