193 
From the absence of production posteriorly of the trochanter, 
the width of its postero-external surface is relatively less broad 
than in Dinornis and, though protuberant and roughly striated 
externally, it presents no marked depressions or elevations. On 
the outer surface of the trochanter an obscure, obtusely angular 
ridge runs from its summit obliquely downwards and backwards. 
A feebly-marked intermuscular ridge (Pl. ii., fig. 1 /’) begin- 
ning to the inside of the rough surface, which corresponds to the 
ecto-trochanteric tuberosity (Owen), descends vertically for two 
inches, and then inclines inwards to merge into a ridge which 
leads to the front of the ento-condyle. Immediately to the out- 
side of the point where the inclination inwards takes place is a 
slightly elevated rough surface which is scarcely manifest in the 
figure. 
The posterior surface of the upper expansion of the bone has 
undergone some amount of distortion by the depression of a con- 
siderable area of its outer crust—(PI. iii., fig. 2 G), but the other 
femora show this tract and, indeed, the whole of the posterior 
surface to have been very flat. The posterior margin of the 
upper articular surface, as this begins to rise on to the trochanter, 
projects considerably so as to form an overhanging ridge. Directly 
below this ridge is a large deep oval depression (PI. i11., fig. 2 /) 
which is clearly a pneumatic orifice. Two large foramina, separated 
by a bony septum, lead from the bottom of the depression into 
the interior of the bone. 
The shaft is remarkably smooth and, with the exceptions above 
mentioned, is devoid of the prominent muscular ridges, rough 
surfaces or elevations that characterise Dinornithine femora ; 
particularly, on the posterior aspect, is there an absence of line 
aspere. One very small nutrient foramen is present at about 
the centre of this surface. 
A characteristic feature of this bone is the marked curvature 
of its internal contour (PI. iii., figs. 1 and 2) in which respect it con- 
trasts with the more open curve in the femora of Dinornis and 
Dromornis. The flatness of the posterior surface has been 
mentioned ; to a hardly less extent the anterior and exterior 
surfaces are flat also, while the inner is rounded. ‘Thus the 
transverse section in the middle of the shaft is a pyriform oval 
with the small end corresponding to the inner surface, or it might 
almost be described as trilateral. 
The lower extremity, of which an area of the crust on the front 
surface has been depressed (PI. iii., fig. 1 G) is, like the upper, 
characterised by its great transverse breadth—the smallest of 
the Callabonna bones exceeding, in this respect, the corresponding 
measurement of a femur of Dinornis giganteus (Owen), in the 
Museum collection, having a length of 15 inches, while the 
