240 PROFESSOR OWEN ON THE GENUS DINORNIS. 
In the twenty-second vertebra (first dorsal) the diapophyses are relatively shorter and 
broader than in D. maximus, the postzygapophysial prominence is much narrower, 
both neural spine and hypapophysis are relatively shorter. 
and narrower than in the preceding (last cervical) vertebra. 
The base of the hypapophysis extends so as to form a ridge coextensive with the 
length of the undersurface of the centrum in the third dorsal. The parial tubercles 
below the postaxial articular surface in the last cervical gradually subside, and dis- 
appear in the third dorsal, in which the hind end of the hypapophysial ridge begins 
to broaden and project. In the fourth dorsal the fore and hind hypapophyses project 
as distinct processes, but are subequal; the anterior one is not produced and curved 
forward as in the fifth (?) dorsal of Dinornis maximus’. The anterior hypapophysis is 
suddenly reduced in the fifth dorsal of D. parvus, and disappears in the sixth, where 
the posterior hypapophysis resumes the transversely parial character, and this part of 
the centrum is more produced backward. The neural spines gradually lengthen after 
the third dorsal, but lose in fore-and-aft diameter. Both fifth and sixth dorsals show 
three pneumatic foramina on each side of the neural arch. 
The length of the vertebral column, as composed of the foregoing twenty-seven 
segments, with those inclusive which compose the skull, is 5 feet. 
The hypapophysis is longer 
§ 4. Ribs. 
The vertebral ribs are in nine pairs, the seven anterior ones having free articulations 
with their respective segments, the two posterior pairs being ankylosed therewith. 
The first three pairs have no corresponding sternal ribs; and those of the seventh and 
eighth do not attain the breast-bone. The ninth pair (PI. LIV. fig. 1, p/ 3) like the 
first are short, straight, and terminate in an obtuse point. The third, fourth, and 
fifth pairs of vertebral ribs (pleurapophyses) retain their diverging appendages 
(Pl. LVIII.). The hemapophyses of the fourth, fifth, and sixth pairs, ossified as 
in the rest of the class, join the ‘sternum,’ both articular extremities admitting of the 
movements affecting the capacity of the thorax; they progressively increase in length, 
and are termed ‘sternal ribs.’ The hemapophyses of the seventh and eighth pairs lose 
length, and terminate freely. 
§ 5. Sternum. 
The part of the skeleton of Dinornis which, after the skull, differs most from that of 
Apteryx’ is the sternum (Pl. LV.). It is true that the character of a pair of poste- 
rior notches with coextensive mesial and lateral boundaries, and the general relations 
* Loc. cit. p. 168, fig. 30. 
? Trans. Zool. Soe. vol. ii. 1838, p. 298, pl. lv. figs. 2, 3. 
