PHYLOGENY OF THE PALZOGNATHE AND NEOGNATHA, 227 
wards, this region of the pelvis in this respect resembling Struthio. In half-grown 
specimens it is quite pre-caudad; in adult birds it becomes fused with the extreme 
postero-dorsal angle of the ischium. 
The ilium increases markedly in breadth during its growth. This increased breadth 
accompanies a corresponding increase in the height of the neural spines of the sacral 
and post-synsacral vertebra, which, as has already been described (p. 208), in the 
embryo are represented only by low cartilaginous transverse ridges. In the embryo the 
pre- and post-acetabular ilia are slightly convex superficially, in the adult they become 
slightly concave. 
The supra-trochanteric process marks the region, more or less, of the sacral vertebre. 
It lies immediately above the anti-trochanter, but does not project outwards as in 
Rhea. One of the most remarkable features of the pelvis of Dromeus and Casuarius 
is the close embrace with which the post-ilia receive the post-sacral vertebre of the 
synsacrum, almost entirely suppressing the para- and diapophysial processes. 
In Dromeus and Casuarius the sacral vertebree extend outwards beneath the vertical 
border of the ilium to articulate with the ascending process of the ischium at its 
junction with the ilium. 
The pelvis of D. ater differs from that of D. nove-hollandie chiefly in that the 
development of the pectineal process is but slight—wherein it approaches Caswarius,— 
and in that the obturator fissure is wider, the rotation backwards of the pelvis being 
less. The crest of the pre-ilium is less arched, 
The pelvis of Dromwus can scarcely be distinguished from that of Casuarius. 
In the young bird (half-grown) the neural spines of the sacral region of the syn- 
sacrum appear to be more transversely expanded than in Caswarius. In the adult the 
pre-ilium appears to be relatively of greater breadth in Caswarius and the post-ilium is 
relatively longer and narrower. ‘The strong <-shaped supra-trochanteric processes 
and the width across from one side to the other are apparently rarely attained by the 
Cassowary. 
Judging from the skeletons in the Museum collections it would seem that in the 
width across the supra-trochanteric process and the relatively long post-ilium, the 
pelvis of Dromeus is readily distinguishable from that of Caswarius. 
Unfortunately, however, these data do not appear to be really reliable, for in a pelvis 
ot C. casuarius the resemblance to these very characteristic points in Dromeus were so 
close as to render it most difficult to distinguish between the two genera. 
In C. bennetti the width across the supra-trochanterie process is as conspicuous as in 
Dromeus, but the whole pelvis is of course much smaller than in Dromeus. 
In the young (half-grown), both of Caswarius and Dromeus, the ischiadic fissure is 
complete. Later in life it is closed by fusion of the extreme antero-dorsal angle of the 
fore end of the ischium fusing with the ilium. In very old birds the width of this 
fissure caudad becomes seriously encroached upon by the downgrowth from the post- 
