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summit), when viewed superiorly, forms an open sigmoid curve 
(Pl. iv., fig. 5, # # H), which is so inclined that its lower and 
outer end is considerably below the level of its upper and inner. 
The former end terminates by a marked backwardly directed 
curve (fH). In fact, the external angle of the cnemial process 
might be described as forming a backwardly directed hamular 
process, the inferior border of which forms the beginning of the 
ectocnemial ridge (Pl. iv., figs. 1, 4, H G). This ridge, or crest, 
is continued downwards, with an inward trend, to a point which 
lies about four inches below the point of the hamular process ; 
here it subsides upon the shaft, having at its termination 
approached to within an inch of the procnemial ridge. 
Internally the cnemial process is bounded by a thick and 
rounded border (PI. iv., figs. 3, 5 D) formed by the meeting of its 
posterior surface with the internal surface of the procnemial 
crest. This border descends abruptly from the summit of the 
process, but with an inclination backwards and inwards (figs. 3, 
5, D). On meeting the upper expansion of the bone this 
descending border becomes continuous with the adjacent, some- 
what elevated and ridge-like anterior margin of the inner part of 
the rotular channel. There is thus no considerable extension of 
the epicnemial crest beyond, and to the inside of, the procnemial 
as in Dinornis, the latter ridge, in fact, springs from the 
interior surface of the former quite close to the thick and 
abruptly descending inner border that has been described. 
Owing to the posterior incurvation of the angle formed at the 
junction of the epicnemial and ectocnemial crests, the ectocnemial 
cavity iying between this angle and the outer margin of the ecto- 
condyle forms a deeply indented bay (fig. 5, opposite /), of which 
the arms approach one another to within two and a half inches. 
No distinct supra-fibular facet is observable ; in fact, when 
the fibula, which nearly certainly belongs to one of the large 
pair of tibio-tarsi, is placed in position, the head of the former 
does not touch that of the latter by nearly half aninch. The 
fibular ridge begins, as a low rising, two inches below the over- 
hanging external edge of the ectocondylar surface, the interval 
being smooth and deeply concave in a vertical direction. An 
inch and a half below its beginning the ridge widens into a 
rough and nearly flat elevated surface, of fusiform outline, for 
articulation with the fibula (Pl. iv., fig. 4, OO). This surface, 
which is four inches long by five-eighths of an inch broad, 
appears to represent the whole extent of the direct articulation 
between the two bones. A smooth interval of about an inch 
succeeds this surface, and below this again an ill-defined broad, 
rough ridge that represents the external surface of the shaft, 
proceeds to the lower outer condyle. The opening of a larg 
