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narrow tract (Fig. 6.) The superior contour line in front of the 
conjoined articular surfaces, though sufficiently distinct to form 
the inferior boundary of the supracondylar space, does not form a 
so marked a ridge as in Dinornis. Posteriorly, the corresponding 
contour line (not very distinctly marked and not distinguishable in 
Fig. 2) slopes downwards and inwards from the summit of the outer 
condylar region to that of the inner where it becomes continuous 
with the compressed and projecting postero-external ridge in 
which the inner condyle terminates behind. 
When viewed from below the intercondylar channels, in front 
and behind, yield contours, the forms of which are seen in PI. iv., 
fig. 7. The same figure shows the greater extent of the anterior 
production of the inner condyle, but it does not show very con- 
spicuously another character which is to be noticed, viz., the 
greater lateral width of the whole trochlear surface in front than 
behind, the last-mentioned feature being due to the fact that, as 
the infero-internal border of the inner condyle sweeps backward 
it also inclines outwards, trending towards the corresponding 
border of the other side, the curve of which scarcely departs from 
a true antero-posterior plane. The degree of curvature of the 
inferior contour of the trochlear surface is shown in Figs. 1, 2, 6. 
The greater part of the front of the inner surface of the 
ento-condyle is occupied by a large gibbous or nearly oval 
depression, of which the margin anteriorly and inferiorly comes 
right up to the edge of the articular surface. (PI. iv., fig. 3, Q.) 
Behind the depression, about midway between the anterior and 
posterior border of the condyle, is an obtusely rounded, epi- 
condylar, tuberosity (Fig. 3, &) which is not very prominent, and 
scarcely projects beyond the plane of the lower border of the 
condyle. 
The external surface of the outer condyle (Fig. 4, H C) is 
nearly flat, or only very slightly concave, over its whole extent, 
and possesses no epicondylar tuberosity. 
The supra-condylar extensor groove (JZ) may be discerned as 
commencing about six inches above the condyle on the outside of 
the ridge () described as leading downwards from the termina- 
tion of the procnemial crest. The ridge is, in fact, continuous 
with the inner border of the groove. (Fig. 6, XZ). 
As the groove descends it deepens, and inclines outwards until 
it reaches the mid line, at which point it is spanned by the 
bridge (fig. 6, S). At this level the groove is deflected inwards 
at a somewhat abrupt angle, and below the bridge the groove is 
distinguishable as a broad, shallow canal, which emerges into the 
wide, but not deep, supra-condylar fossa. Of the borders of the 
groove, the inner (ZL) is the more prominent and rugose, and the 
outer (Jf) smooth. The bridge itself, median in position, and 
