194 
similar width in the largest approaches to within half an inch of 
that of Dinornis maximus (Owen) with a length of 18} inches. 
Conformably to the great width of the lower extremity is the 
breadth of the rotular channel (2£ inches) (PI. iii., fig. 4. R C) which 
also slightly exceeds the breadth of this channel in the femur of 
D. giganteus (Owen). At the same time the channel is, in 
Genyornis, relatively shallow. The anterior intercondylar ridge 
is very slightly indicated (Pl. ii., fig. 4 V), while the posterior is 
narrow and prominent (PI. iii., fig. 2 O) ; the region corresponding 
to the intercondylar fossa is prominent rather than depressed. 
Owing to the gentle inclination of the posterior surface of 
the shaft, as it leads into the popliteal fossa (Pl. ii., fig. 2 J), 
this depression is ill defined as to its superior contours, and the 
external and internal ridges which bound it laterally are broadly 
rounded, especially the former. The floor of the fossa is flat, 
but rough, and there are large pneumatic orifices arranged in 
a row along the lower margin (Pl. ii, fig. 2, above 0). The 
larger depression seen at a higher level is probably accidental, 
as it does not appear to exist in the other bones. The open 
and shallow characters of the fossa in this bone contrast 
with the better defined, oblique, deep and narrow cavity in 
D: omornis. Commensurate also with the great breadth of 
the lower end is the width of the ento-condyle (PI. iii., fig. 4 IC), 
of which the contour of the posterior margin forms nearly a 
horizontal line (17) before it dips suddenly to become the internal: 
margin of the posterior intercondyloid notch (); the contour 
of this notch forms a U-shaped figure instead of a more open 
curve. 
Of the ecto-condyle(# C) the tibial moiety is also relatively wide, 
exceeding, in this respect, the corresponding part in Dinornis 
giganteus, and the tibular groove, is continued fowards for a con- 
siderable distance on to the front of the ecto-condyle; just behind 
the posterior limits of the groove there is an irregularly elongated 
ecto-condylar fossa (Pl. 111., fig. 2 P). The depression on the 
outer surface of ecto-condyle is inconspicuous, beside that to be 
observed on most Dinornithine birds. The ecto-condyle, moreover, 
when the bone is held vertically reaches a considerably lower 
level (14 inch) than the ento-condyle; thus to place the bone in 
the position that the most inferior part of each condyle rests 
upon the same horizontal level involves a very considerable 
obliquity of the shaft. 
Except in respect of size, all the Lake Callabonna femora 
resemble one another so exactly, that there can be no doubt 
that they belong to the same species. We have elsewhere 
expressed the opinion* that two fragments of femora from 
* Trans, ‘BR. ‘Soc., 8.4., vol: XX, p 175. 
