I 



PROFESSOR OWEN ON THE GENUS DINORNIS. 315 



small existing Struthious bird of New Zealand than the larger species of New Holland. 

 In the Emeu, for example, the inferior spinous process begins not to be developed until 

 the dorsal series of vertebrae, with articular cavities for ribs, commences. 



The anterior articular surface of the body (Plate XLI. figg. 2 & 3, a) bends down upon 

 the under part of the vertebral body, where the lower angles of the reniform surface are 

 produced backwards. The diapophyses or transverse processes {ib. d) developed from 

 the base of the anterior oblique processes {ib. z) seem not to have been connected by a 

 costal process with the produced margins of the anterior and under part of the body (a), 

 but to have been divided from these by an open groove on each side. The perforated 

 depression (i, fig. 1) is smaller than in the foregoing cervical vertebra, and the posterior 

 boundary ridge of the foramen pneumaticum is shorter and more obtuse. The base of 

 the superior spine is strongly impressed before and behind by a rough surface for attach- 

 ment of the inter-spinal elastic ligaments : the anteroposterior extent of this spine (g) 

 and of the inferior one (Ji) is shown by dotted hues in fig. 1 . Both having been broken 

 off in the specimen, these and the other fractured surfaces of the vertebrae show the 

 very coarse and loose cancellous texture of the bone. 



In a similar-sized more perfect posterior cervical vertebra of Dinornis giganteus, in the 

 collection of Mr. Percy Earl, obtained from the same deposit and locality, the strong 

 spinous process is entire : it is four-sided and truncate at the summit, four inches high 

 from the fore-part of its base, one inch in the antero-posterior diameter of the base, 

 and ten lines in the transverse diameter. 



A fragment of a vertebra, from the same collection, of nearly the same size, and pro- 

 bably a little anterior in position, differs from the preceding in having only a very shal- 

 low imperforate depression, where the deep perforated pit exists at the sides of the 

 neurapophyses in the foregoing vertebra : the neural spine has scarcely been developed 

 above the level of the posterior zygapophyses or articular processes in this fragment. 



Dr. Mackellar's collection contained two very perfect specimens of dorsal vertebrae 

 of smaller species of Dinornis, presenting several peculiarities characteristic of the 

 genus. The first of these (PI. XLII. figg. 1 & 2) is from the middle of the dorsal region 

 of probably the Dinornis ingens. It is not carinate inferiorly, as in the corresponding 

 vertebra of the smaller species, figured in PI. XVIII. a, figg. 6^ — 9, vol. iii., and the 

 lower border of the anterior articular surface of the body is less produced in proportion 

 to that of the posterior surface. The depression leading to the cancellous structure 

 between the transverse and posterior obUque process in the small dorsal vertebra above 

 cited is wanting in the present large one ; but the pneumatic foramen (PI. XLII. /) be- 

 tween the costal depression (c) and transverse process (6) is present. The proportionate 

 breadth of the body of the vertebra ; the broad outspread oblique processes {ib. fig. 2,z,z'); 

 the thick, obtuse and almost horizontal transverse processes {ib. b.) ; the strong spinous 

 process, as broad transversely as antero-posteriorly ; — all exemplify the generic charac- 

 ters of the vertebrae of Dinornis. 



