260 PROFESSOR OWEN ON THE GENUS DINORNIS. 



breadth of its under surface, and the thick four-sided spinous process ; but one {v 2)' 

 is broader in proportion to its length than the other {v 3). The more slender vertebra" 

 has a thicker spinous process, which, at the same time, is more compressed from be- 

 hind forwards : the cavity behind the spine is deeper and more angular, as is also the 

 notch between the posterior oblique processes. The anterior articular processes are 

 raised higher above the body in the more robust vertebra, v 2 The anterior articular 

 surface of the vertebra v 3 has a much less vertical extent than in the thicker vertebra ; 

 and the inferior spine (h) is narrower, but of greater antero-posterior extent, and is 

 situated nearer the posterior part of the body. Both these vertebrae have the orifices 

 at the sides of the neural arch which communicate with the interior loose cancellous 

 structure. These are not present in the Apteryx, the corresponding vertebree of which 

 in other respects more nearly resemble the present in general form and proportions' 

 than do those of the other existing Struthionidee. 



The vertebra v 4,' from New Zealand, transmitted to me by Dr. Richardson, the author 

 of the ' Fauna Boreali-americana,' belongs to the same species as the vertebra v 2. It is 

 either the first or second of the dorsal series : the inferior transverse processes manifest 

 part of the concavity for the articulation of the head of the rib, and there is a spinous 

 process Qi) from the under surface of the body of the vertebra, which, as in the anterior 

 dorsal of the Apteryx, is less broad and flattened than in the anterior cervicals. 



Of the difference of the character of this vertebra, as compared with the correspond- 

 ing one in the Ostrich, the figures' give a better idea than can be conveyed by verbal 

 description. The upper transverse processes are continued, as in the first and second 

 dorsals of the Apteryx, from the anterior part of the whole side of the neural arch, not, 

 as in the Ostrich, from near the summit ; these processes also, as well as the spinous 

 process, are considerably thicker and stronger than in the Ostrich. In regard to the 

 spinous process, the Dinornis, in the squareness of that part, differs as much from the 

 Apteryx, in which the dorsal spines are compressed laterally and extended antero- 

 posteriorly, as from the Ostrich. 



The last vertebra, i; 5, of the Dinornis in the present collection that remains to be 

 noticed, is from the middle of the dorsal region : it belongs to a smaller species than the 

 preceding ; most probably to the Din. didiformis. 



The body* is laterally compressed, and terminates below in a median carina, which 

 has a concave outline : it has the characteristic shortness as compared with the breadth 

 of the vertebrte in this genus ; the anterior articular surface' is more concave from side 

 to side, and the posterior surface more convex in the same direction than in the corre- 

 sponding vertebrae of the Ostrich or Apteryx : both these surfaces have an unusual ver- 

 tical diameter in proportion to their breadth. 



' PI. XVIII. figs. 4, 5, 6 « PI. XVIII. figs. 7, 8, 9. ' PI. XVIII. fig. 10. 



< PI. XVIII 0. figs. 1, 2, .3. -' PI. XVIII a. figs. 3 & 4. ' PI. XVIII a. figs. 6 & 9. 



' PI. XVIII a. fig. 8. 



