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, PI. 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 (/) and pubis (o). 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, I) to view. In the Chimpanzee, 

 the twist, being carried further, brings the inner surface of the pubis (o, 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, I) 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, i). 



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-pectinoea,' 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 

 PI. XII., with the ^rst sacral vertebra in the Human skeleton (fig. 1) : the second and 

 part of the third sacral vetebrse, so determined in the Gorilla, articulate with the iliac 

 bones as in 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 VII. 

 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 orominent surface above the outer condvle. 



