316 PROFESSOR OWEN ON THE GENUS DINORNIS. 



The rough Hgamentous tract on the fore and back part of the neural spine is produced 

 into a median ridge (s), making the transverse section of the middle of the spine hex- 

 agonal ; two inches and a half of the spine remain, measured from the bottom of the rough 

 tract ; the height would probably have exceeded three inches in the perfect vertebra. 



A dorsal vertebra (PI. XLII. figg. 3 & 4) of the same size, and from the same or nearly 

 the same region of the spine, shows the pneumatic foramen between the transverse and 

 posterior articular process, as in the small vertebra (vol. iii. PI. XVIII. a, figg. 6 — 9) ; 

 and it further differs from the vertebra, PI. XLII. figg. 1 & 2, by the larger proportional 

 size of the zygapophyses {ib. z, z) and the somewhat more slender spine {ib. s) : the 

 ridge continued from the side of the base of the spine to the transverse process {ib. b) 

 is sharper. 



A middle or posterior dorsal vertebra of a smaller species of Dinornis resembles the 

 larger one in the absence of the pneumatic foramen between the posterior oblique and 

 transverse processes, and in the relative size of the posterior and anterior articular pro- 

 cesses : the spine is entire, the rough front and back surfaces are not carinate, but 

 convex ; the summit of the spine flat and truncate. 



The figures in Plate XLII. supply the points of comparison omitted in the verbal de- 

 scription, in a better and more applicable form. I suspect one of the larger dorsals to 

 belong to the Bin. ingens, the other larger one to the Din. crassus ; the present vertebra 

 may well belong to the Din. struthoides. 



Sternum. 



From the turbary deposit near Waikawaite Mr. Earl obtained nearly an entire sternum 

 (PI. XLIII. figg. 1 — 3) of one of the larger, if not of the largest species of Dinornis. It 

 appeared to have been fractured by the instruments employed in digging out the bones, 

 and reached me in two pieces, one including the articulations for the sternal ribs (r, r) 

 and for the coracoid {ib. fig. 2, c, c) of the right side, with rather more than half the body 

 of the sternum, and with the border of the right posterior wide notch (e) entire, showing 

 its size and shape, but with part of the anterior border and the anterior (a) and posterior 

 {p) angular processes broken away : the left portion of the same sternum included the 

 two posterior articular surfaces for the ribs and upwards of three inches of the posterior 

 angular process, with part of the entire border of the left posterior emargination (e) : 

 the base {x) of a process from the middle of the posterior border of the sternum indicated 

 the characteristic configuration of this part of the bone. The anterior border (fig. 2), 

 about half an inch thick, and rounded, is shown by the right moiety to have extended 

 almost straight to beyond the middle of the bone. The outer surface of the sternum 

 is gently convex, without the smallest trace of a median crest or keel ; the inner surface is 

 slightly concave, deepest near the anterior angles. The main body of the sternum con- 

 sists of a light cellular layer of bone, with a thin, smooth, compact outer and inner table, 

 the whole averaging three lines in thickness, and thinning off to the posterior margin. 



