12 MR. ST. GEORGE MIVART ON THE 
Tue Inium (figs. 2 & 8, 77). 
This bone extends itself over twenty-two vertebra, namely from the twenty-third to 
the forty-fifth inclusive. Compared with the same bone in Struthio, its dorsal margin 
is more convex, its anterior margin more concave (the ventral preaxial angle being more 
prominent), and the postacetabular part is not so much in excess of the preacetabular 
portion. It would taper preaxiad but for the ossification (before mentioned) of the 
ilio-ischiatic ligament which causes it to expand vertically towards its distal end. ‘The 
gluteal lines do not descend (ventrad) so much as in Struthio; and the stronger supra- 
acetabular process comes to jut out more horizontally as well as more strongly, making, 
with its fellow of the opposite side, a flat rhomboidal surface on the dorsum of the 
ilium. The ilia are flattened against the included postacetabular vertebre to a 
remarkable degree. 
Tue Pusis (fig. 2, p). 
This bone is like what that of Struthio would be if the latter were sharply cut off at 
the postaxial end of the ischium ; only it is not quite so much bowed outwards. ‘There 
is, of course, no pubic symphysis. In the young it does not join the ischium distally, 
but quite resembles the osseous part of the pubis of the young Ostrich when the sym- 
physial part is all cartilaginous, 
Tue Iscuium (fig. 2, 2). 
This bone is very slightly, if at all, shorter than the pubis, and ankyloses postaxially 
both with that bone and with the ilium. It seems to form about the ventral third of 
the antitrochanteric process. It also slightly ankyloses with the pubis more proximad, 
so as to cut off the anterior part of the obturator foramen as a separate and much smaller 
foramen (fig. 2, between Jp & ps). The two ischia unite together postaxially a little 
behind the acetabulum, and thence expand transversely as they proceed postaxiad, 
forming an elongated sheet of bone (concave in both directions on its ventral surface) 
beneath the sacro-caudal vertebre. At its distal end it sends down a process, curving at 
first ventrad and then preaxiad, which ankyloses with the extreme distal end of the 
pubis. Thus, as it were, the outer ridge of the ischium of Struthio is drawn out, while 
the surface between the (here relatively approximated) dorsal and ventral ridges coalesces 
with the corresponding surface of its fellow of the opposite side. 
THE VERTEBRAL RIBS (fig. 1). 
There are nine vertebral ribs, the first and last becoming in the adult (as in Struthio) 
ankylosed transverse processes. The fourth, fifth, and sixth of these bones unite with 
sternal ribs. (See fig. 1.) 
The jirst rib is attached to the fifteenth vertebra, and ankyloses with it in the adult. 
It is very small, triangular, and very little longer than broad. 
