162 PROFESSOR OWEN ON THE GENUS DINORNIS. 



The under surface of the tenth cervical, ib. C 1 0, is widely grooved, with the hyp- 

 apophysial tubercles deepening the fore part of the sides of the groove. Slightly con- 

 verging ridges from the upper part of the posterior zygapophyses represent the neural 

 spine. 



These ridges converge as they advance upon the neural arch, in the ninth, eighth, 

 seventh, sixth, and fifth cervicals, in which a low tuberosity on the fore part of each 

 ridge represents the divided neural spine. The under surface of the centrum becomes 

 flatter in the above vertebrae : the hypapophyses are represented by a tubercle on the 

 lower part of each parapophysis. 



In the fourth cervical, ib. C 4, the pair of tubercles representing the neural spine are 

 longer : in the third cervical they are closer together : in the second they have coalesced 

 to form a single spine, with a deep fossa at its back part : in the atlas, ib. I , the neural 

 spine is obsolete. 



The hypapophysis in the third cervical is a single median ridge, as it is also in the 

 axis, or second vertebra : in the atlas it is absent. The hind surface of the body of the 

 atlas is convex, a little hollowed above to receive the odontoid process : the lateral 

 ' vertebral ' canals are defined each by a slender vertical bar of bone. The under surface 

 is produced into a pair of short tubercles at its hind margin and at its front margin ; 

 and they project respectively backwards and forwards, not downwards as hypapophyses. 

 The deep anterior cup, which receives the single occipital condyle, is notched at the 

 middle of its upper part. The neural arch expands beyond the breadth of the centrum, 

 and developes only the posterior pair of zygapophyses. 



The pelvis of the Dinornis elephantopus (PI. XLVI. S 63, 64) is one foot nine inches 

 in length, contrasting extraordinarily with the size of the skull. 



Six of the anterior sacral vertebrae have parapophyses with the ribs confluent with 

 them, save in the first: beyond the second vertebra the ribs simply abut against the 

 .ilium, with which they are confluent. 



The ischium, 63, and pubis, 64, which coalesce with the ilium to form the acetabu- 

 lum, do not again unite with each other : the notch at the under and fore part of the 

 ischium opens into the long interspace between the two posteriorly extended bones. 

 This part of the pubis, 64, is straight and styliform, 8^ inches in length ; slightly 

 expanded, to a breadth of 14 lines, near the end ; flattened externally, convex internally, 

 so as to offer a subtrihedral transverse section. The ischium, 63, with an upper and 

 lower notch, having smooth and thick rounded borders, near the acetabulum, expands 

 gradually, and is flattened, into a plate of about three inches of vertical depth, with a 

 truncate termination. 



Nine caudal vertebrae, of a transversely subquadrate form, with a contracted neural 

 canal, surmounted by a low transversely extended arch supporting a pair of tubercles, 

 represent the basis of the short tail of the Dinornis. 



The last of these vertebrae is as small and simple as in other large birds devoid of the 

 power of flight ; showing nothing of that characteristic modification of the terminal 



