PEOFESSOH OWEN ON THE GENUS DINOENIS. 247 



iliac bones are continuously confluent. The ischium, receding from the acetabulum, 

 expands vertically, and converts the 'ischiadic notch' into a foramen by junction with 

 the ilium ; near its acetabular origin it sends down a feeble prominence to denote the 

 hind boundary of the ' obturator foramen,' which is thus a mere notch widely commu- 

 nicating with the space between the ischium and pubis, beyond which the latter bone 

 extends for some distance in both the Dido and the Solitaire. 



§ 7. Caudal Vertelrce. 



The free, or proper, caudal vertebrae of Dinornis parvus are eleven in number ; but 

 the tenth has coalesced with the eleventh (PI. LIV. figs. 2-7). The first caudal 

 resembles the last sacral in the vertical extent and general thickness of the transverse 

 processes ; but these have not the length of those of the otherwise similar vertebrEe in 

 which such processes are confluent with the ilia. The under surface of the centrum is 

 irregularly grooved lengthwise, not smooth as in the antecedent vertebra ; the neural 

 arch sends ofl' a pair of short, thick, obtuse processes, representing a bifid neural spine, 

 which seems to have had ligamentous junction with the hind part of the neural arch in 

 advance, a median prominence of which has been continued by ligament into the inter- 

 space of those processes. 



The centrum of the second caudal vertebra shows the same irregular inferior grooving 

 as the first ; the loss of size in the second is chiefly due to the minor development of 

 the transverse processes, from each of which slightly project a diapophysial and para- 

 pophysial prominence. The neural arch here also sends ofl' a pair of short, but more 

 divergent, obtuse processes, defined by an anterior notch. The third caudal loses 

 breadth ; but this dimension continues the same to the seventh caudal inclusive. The 

 transverse processes gradually diminish ; and the indication of their double nature 

 disappears at the sixth caudal ; the short stumpy bifid character of the neural spine 

 is continued, with slight diminution of size, to the eighth caudal inclusive. In the 

 ninth it is represented by a single tubercle ; in the tenth it disappears and the neural 

 canal is there closed. A fine vertical line descending from a puncture, which may 

 have transmitted a nerve-filament from the end of the neural axis, and a transverse 

 pair of notches on the under part of the centrum are the indications of the primitive 

 development of the seeming terminal vertebra from two cartilaginous rudiments. The 

 ossified confluent result exceeds in length that of any of the antecedent caudals, and, 

 besides the absence of neural spine, gradually narrows to a rough termination of 2 lines 

 inferior breadth ; the sides of the eleventh vertebra converge to an upper ridge (ib. 

 fig. 3). 



The base of the terminal coalesced vertebrae (ib. fig. 7, lo, ii) is more rough and 

 irregular than in the two antecedent caudals ; in the rest of these vertebrae a similar 



