248 PROFESSOR OWEN ON THE GENUS DINORNIS. 
or double-ridged character of the centrum (as shown in figs. 4, 5 and 6) is indicative 
of the attachment of depressor muscles. 
The caudal vertebre in natural articulation curve slightly downward at the terminal 
third of the series. The length of this series following such curve is 5 inches 3 lines. 
In the skeleton of Dinornis elephantopus', described and figured in Trans. Zool. 
Soc. vol. iv., nine caudal vertebre were definable, most of them more or less muti- 
lated, but the last one sufficiently preserved to show the absence of the characteristic 
modifications of that part of the tail-skeleton in most birds of flight”. ‘The caudal 
vertebra of Dinornis maximus, described in the Memoir (part xxii. fig. 36) as the second 
of the series, corresponds in the main with the second in D. parvus; but the divisions 
of the neural spine, or divergent processes from the roof of the neural arch, are rela- 
tively longer than in D. maximus, and the interspace is consequently deeper and wider. 
In the three coalesced terminal caudals of, probably, Dinornis crassus, described p. 180, 
loc. cit., and figured (figs. 58, 39), the better-marked indications of the line of confluence 
of the penultimate and last vertebra bear out the interpretation of the corresponding 
feebler ones in ). parvus; but the parapophysis of the last vertebra in D. crassus is 
not developed in the smaller species. The foramen indicative of the exit of the hind- 
most nerve is relatively longer in D. crassus, and is repeated on both sides. The 
antepenultimate caudal in D. crassus is relatively shorter than in D. parvus. Of the 
three sides of the terminal coalesced caudals in D. parvus, the lower one is the 
narrowest, not the broadest as in D. crassus. The penultimate centrum of D. parvus 
has not the excavation of the lower surface which is described and figured in that 
centrum of D. crassus. But all the essential modifications of this part of the skeleton 
in the present extinct wingless genus of birds are repeated in Dinornis parvus, and are 
manifested with slight modifications in the caudal vertebre of Apterya*. 
§ 8. Femur. 
Notwithstanding the extreme difference of size, the femur of Dinornis parvus (Pl. LVI. 
figs. 1-6) presents the generic characters of the bone as well marked as in Dinornis 
maximus*, and as clearly differentiated from those of the femur of Apteryx australis. 
The only trace of a transition is in the slight degree of relative slenderness of the shaft 
to the length of the bone as compared with that in the taller species of Moa; but all 
the characters connected with muscular power or work are as strongly marked in 
D. parvus as in any of the larger forms of the genus. The thickness of the wall of 
’ Memoirs, &c., 4th, 1878, p. 223, pl. lx. Ibid. p. 233. 
* In Chauna chavaria the caudals precede the coalesced group of four, the foremost of which barely surpasses 
in height the preceding free caudals. (See the excellent and exhaustive work by Eyton, ‘ Osteologia Avium,’ 
pl. 25a. fig. 3). 
* Trans. Zool. Soc. vol. i. p, 288. 
* Trans. Zool. Soc. vol, vi, 1868, p. 498, pl. lxxxix. 
