240 PEOFESSOE OWEN ON THE GENUS DINOENIS. 



In the twenty-second vertebra (first dorsal) the diapophyses are relatively shorter and 

 broader than in J), maximus, the postzygapophysial prominence is much narrower, 

 both neural spine and hypapophysis are relatively shorter. The hypapophysis is longer 

 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 3 feet. 



() 4. Hibs. 

 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,^/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 

 (PI. LVIIL). The hoemapophyses 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 aflecting the capacity of tlie thorax ; they progressively increase in length, 

 and are termed ' sternal ribs.' The hsemapophyses 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 (PI. 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. Soc. vol. ii. 1838, p. 298, pi. Iv. figs. 2, 3. 



