PROFESSOR OWEN ON THE GENUS DINORNIS. 249 
the cavity of the shaft and the expanse of the distal end of the femur are dinor- 
nithic. 
In carrying out comparisons with previously determined species of the genus, I find 
that, the least diameter of the shaft being one seventh the length of the femur in 
D. parvus, the entire bone is relatively less thick than in Dinornis geranoides', and the 
distal end is relatively less expanded than in Dinornis didiformis*. The trochanter 
(Pl. LVI. figs. 1, 2, c) shows rather less relative height than in D. didiformis, but 
presents equal breadth. The distal end has greater relative breadth, especially of 
the rotular concavity (ib. fig. 1, 7), compared with the length of the femur and the 
diameter of the shaft, than in Dinornis geranoides. The muscular ridges are as 
strongly developed on the hinder or popliteal aspect of the shaft (fig. 2), and the 
popliteal space (ib. figs. 2 & 6, @) is as deeply excavated, as in any other species 
of Moa. 
The rough, deep, oval depression (ib. fig. 2, g) reappears at the same part above the 
outer condyle (¢). The outer surface of the great trochanter (fig. 4, c) shows a broad 
longitudinal angular depression, beneath which the distal part of the narrowing 
trochanter is indented by a narrower and shallower longitudinal one (fig. 4, 4). From 
the fore border of this depression is continued the intermuscular ridge (fig. 1, 7), which 
runs straight down the middle of the fore part of the shaft to within one third of the 
distal end of the bone. 
The full, oval, flat, rough surface (fig. 1, d@) on the fore part of the femur, midway 
between the head of the bone and the trochanter for the insertion of the ‘iliacus 
internus’ muscle, is well defined; it is nearer the middle of that part of the bone than 
in the femur of Dinornis elephantopus. The oblong rough surface at the hind part 
of the base of the great trochanter for the insertion of the strong tendon of the ‘ obtu- 
rator internus’ is also well marked*. From this a linear rising or ridge (ib. fig. 2) 
descends along the inner side of the shaft parallel with the anterior ridge. On the 
outer and back part of the trochanterian enlargement are two oblique parallel ridges 
extending downward and backward; the lower one is the strongest and longest. ‘I'wo 
linear ridges extend down the back of the femoral shaft, converging, and terminating 
in a single ridge at about one third of the length of the femur from the distal end. 
The medullarterial canal (fig. 2, 4) opens, as in other Moas, between the hinder 
ridges a little way above their confluence, at the mid length of the bone. 
In the femur of Dinornis ingens and in that of D. struthioides, at the middle of the 
back of the neck of the femur, a seemingly vascular foramen, bigger than the rest 
thereabouts is figured. A foramen in the corresponding position is relatively larger, 
more marked, in D. parvus (fig. 2); it might be taken for a ‘foramen pneumaticum,’ 
1 Trans. Zool. Soc. vol. v. 1865, p. 400, pl. Ixy. * Thid. vol. iii. 1843, p. 249, pl. xxiv. 
® The muscles in relation to the above femoral characters are determined from the analogy of Apteryx 
australis. See Trans. Zool. Soc. vol. iii. 1842, p. 291, pls. xxxii., xxxiii. 
VOL, XI.—PaRT vill. No. 3.—January, 1883. 29 
