14 PROFESSOR OWEN ON THE OSTEOLOGY OF 
much larger, especially in breadth, the outer part being produced in an angular form, 
and giving a concave instead of a convex contour to the lower and lateral outline of the 
pelvis, in a front view (comp. figs. 1 & 2, Pl. XII.). 
The lower portion of the os innominatum formed by the ischium and pubis is bent 
or twisted upon the upper portion in different degrees in Man, the Gorilla, and the Chim- 
panzee, as is shown in the position of the bone selected for the figures of Plate VI. 
In Man, when you look directly upon the plane of the outer surface of the ilium, as in 
fig. 4, the same plane is seen, but obliquely, of the ischium (J) and pubis (0). In the Gorilla 
the twist at the acetabular junction of the bones is such as to cause the lower half of 
the innominatum to present only its ischial margin (h, 1) to view. In the Chimpanzee, 
the twist, being carried further, brings the inner surface of the pubis (0, m) obliquely 
into view. We have, at the same time, as many different views of the acetabular 
cavity ; the whole of which is seen, but obliquely, in Man, but only a very small portion 
(k, 1) in the Chimpanzee, the Gorilla being intermediate in this as in most other respects. 
The most marked distinction from the Human type in the pelvis of the Gorilla is, 
perhaps, the expanse of the ischial tuberosities, which form outward angular projections, 
and cause a concomitant change in the pelvic contour, as already remarked. The sym- 
physis pubis, also, is longer, and descends less obliquely to the point of divergence, 
than in Man. 
In the acetabulum (PI. VI. fig. 2) the depression (i) for the synovial gland and for 
the attachment of the ligamentum teres is relatively larger, and the cotyloid notch is 
narrower and deeper, than in Man (ib. fig. 4, 7). 
The obturator foramen (PI. XII. fig. 2)is smaller in proportion to the size of the bones 
composing it than in Man (PI. VI. fig. 4, p): the oblique groove at the upper and outer 
part is less deep. The ‘ linea ileo-pectinza,’ dividing the ‘ false’ from the ‘ true pelvis,’ 
is less marked in the Gorilla than in Man; but its continuation from the ilium upon 
the sacrum determines the homology of the vertebra below the one marked 5 in fig. 2, 
Pl. XII., with the first sacral vertebra in the Human skeleton (fig. 1): the second and 
part of the third sacral vetebra, so determined in the Gorilla, articulate with the iliac 
bones asin Man. The ‘ false pelvis’ is relatively longer and more shallow in the Gorilla. 
The inlet of the‘ true pelvis’ is less contracted anteriorly, less cordate and more fully 
elliptical in shape : the axis of the pelvis is less oblique, and forms a more open angle with 
that of the trunk in the Gorilla. 
Femur.—Plate VIL. 
The chief or most obvious characters which distinguish the Human femur from that 
of the Quadrumana, up to and including the Gibbons, are,—the greater length of the bone, 
both absolute and relative to the trunk ; the more angular and less cylindrical shape of the 
shaft ; the forward bend of the shaft; the greater length of a well-defined neck; the 
more sudden and greater proportional expanse of the distal end, especially at and above 
the inner condyle ; the greater backward production of both condyles, especially of the 
inner one; and the more flattened or less prominent surface above the outer condvle. 
