1900.] SHUFELDT—OSTEOLOGY OF THE STRIGES. 697 
boundary of the pelvis. The preacetabular superficial iliac area is 
nearly double the extent of the postacetabular. The antitrochan- 
terian facets that surmount the cotyloid cavities have the usual 
backward direction, though their surfaces look downward, outward 
and a little forward. The external surfaces of the ischia look upward 
and outward, having just the reverse direction ventrally. Poste- 
riorly these bones are produced beyond the ilia into finely-pointed 
extremities, tending to approach each other. The slender pubic 
bones, after closing in the obdurator foramen on either side, 
touch and unite with the inferior borders of the ischia as far as the 
pointed ends of the latter, beyond which they are produced nearly 
to meet behind. The circular and thoroughly perforated acetabula 
are formed in the usual manner by the three pelvic bones. They 
have a diameter of about three millimetres, and their circumfer- 
ences are in the vertical plane. The ischiadic foramina are ellipti- 
cal and large; they are, as usual, posterior to the acetabular and 
above the obdurator foramina. These last are also elliptical and 
about one-third the size of the others. Viewing the pelvis ven- 
tralwise, we observe, in addition to points mentioned when speak- 
ing of the sacrum, the reduplication of the ilia, forming pockets 
behind and internally, that open outward through the ischiadic for- 
amina and inward into the general pelvic cavity. The narrowest 
part of the pelvis measures 1.2 centimetres, the widest 2 centi- 
metres, being taken between the iliac projections over the ace-— 
tabula; the average length, including anterior neural spine, is 3 cen- 
timetres. Pneumatic foramina occur in the shallow anfractuosities, 
between the antitrochanters and gluteal ridges in the ilia. None 
of the caudal vertebrz are grasped by the pelvis, the posterior ex- 
tremity of the sacrum always assisting to form the posterior pelvic 
border. The usual number of these vertebre is seven, though oc- 
casionally an additional one is found, making eight in some indi- 
viduals. This enumeration does not include the modified and ulti- 
mate coccygeal vertebra, the pygostyle. They are all freely mova- 
ble upon one another, and the first upon the last sacral vertebra. 
The articular facets upon the centra vary in shape throughout the 
series ; that upon the first is long transversely, with a double con- 
vexity so arranged as to accommodate itself to the one on the ex- 
tremity of the sacrum ; they soon become uniform, to pass to the 
subcircular one existing between the last vertebra and the pygo- 
style, on which it is concave. 
