200 
placed very obliquely, stands prominently forward, especially in 
regard to its lower edge.* 
The width of the bridge is 15 mm. at its outer end, from 
which point the breadth increases towards the inner side, the in- 
crease being due to the increasing obliquity of the upper border. 
Owing to the loss of a small piece which has been chipped out of 
the upper border near the inner pier the width at this end can- 
not be exactly stated, but would appear to have been 19 mm. 
The lower border of the bridge is considerably thicker than the 
upper, and somewhat everted. The lower outlet is oval, and its 
plane looks downwards and inwards, while the upper outlet 
forms a shorter, as well as narrower, oval than the lower. 
In the canal covered by the bridge is a large pneumatic 
foramen which encroaches on the outer pier. 
Close to the outer edge of the bone, and on a level with the outer 
pier, is a rough, obtusely conical tuberosity. (Fig. 6, 7’). In con- 
formity with the more median position of the bridge, as compared 
with Dinornis, that tract of the lower expansion which lies internal 
to this structure, is much wider in Genyornis than in the New 
Zealand genus, and the continuation of this tract below the 
bridge, which forms the incline into the supra-condylar fossa, is 
in the former broad and somewhat transversely convex, in con- 
trast to the condition in Dznornis, where it is pinched into more 
or less of a ridge. The distance from the middle of the lower | 
border of the bridge to the nearest point of the internal condyle 
is 28 mm. 
The dimensions of one of the large pair of tibio-tarsi are shown in 
Table II. Owing to the absence, or distortion, of parts of the 
upper end, it is impossible to state accurately the length in the 
great majority of specimens. That feature which is most per- 
fectly preserved in nearly all of them is the lower end, and we 
therefore use the lateral width dimension of this for the purposes 
of comparison in point of size. We find that, among 24 tibio- 
tarsi in which perfection of the lower end permits accurate 
measurement to be stated, the width varies from four inches in 
the largest example to three and a quarter in the smallest. All 
but eight have a greater measurement than three and a half 
inches, and in none of the bones is there any evident sign of an 
immature condition. 
* The bridge is absent in both the large and nearly perfect pair of tibio- 
tarsi, and, in fact, from all but four of the specimens. The details re- 
specting it are therefore taken from another specimen (that represented in 
fig. 6), comprising only the lower extremity and part of the shaft. 
In this the feature in question is perfect except for a small piece which has 
been chipped out of its upper border... Vide Trans. Roy. Soc. S.A, Vol. 
XX., p. 185. 
