152 



PELVIS. 



wings, the anterior part seems deficient, the 

 anterior superior spine'(a) being placed directly 

 over the cotyloid cavity ; and the crest (c) 

 being, consequently, very short, terminating 

 abruptly at the vertical rib mentioned in the 

 description of the human ilium. The ales 

 are more expanded in the Uran than the 

 Chimpanzee. The crest does not present the 

 lateral /-like curvature, and is less arched 

 than in man. The anterior iliac spines are 

 more widely separated, the inferior (6) being 

 scarcely discernible, and the border between 

 them thin and concave. The posterior, or 

 iliac tuberosity is even less prominent in these 

 animals than in the lower order of Ruminants. 

 The distance from the cotyloid to the sacro- 

 iliac joint is 3^ inches in the Hunterian Chim- 

 panzee, and about 3 inches in the Uran, though, 

 from the greater straightness and obliquity of 

 the cotylo-sacral arch (r/) and the want of the 

 anterior curve, the direct horizontal distance 

 between these points is about the same as 

 in man. 



In the Simice generally, the ilia are said to 

 be placed almost in a straight line with the 

 spinal column. Added to the great length 

 of the ilia, this arrangement causes the pelvic 

 brim to be much elongated from before back- 

 wards ; but much less so, however, than it 

 would be if the pubes and iliac shafts were in 

 the same plane. I have, however, found the 

 ilio-verlebral angle in Chimpanzee, Uran, long- 

 armed Gibbon, and brown Baboon to be very 

 little, if at all greater than the human pelvi- 

 vertebral, as far as could be ascertained without 

 actual section of the bones. But in the Lemurs 

 the ilia are only 10 from being in the same 

 straight line with the spine ; while in the Man- 

 drill and many Monkeys they are almost pa- 

 rallel. This characteristic, heightened by that 

 of the much diminished curve of the lumbar 

 vertebra and the elongation of the iliac shafts 

 in these animals, contributes to form a great 



Fig. 92. 



Pehis of the adult Chimpanzee, anterior view. 



contrast with those of the human pelvis. In 

 the Uran, a projection of the sacro-iliac joint in 

 front is observable, and a solidity of the shafts 



of the ilia. Blainville remarks, that the sacro- 

 iliac facet is oval in these animals. 



The isckia, in common with the whole 

 pelvis, are longer in the Chimpanzee than in 

 the Uran ; and the ischial tuberosities (e) more 

 turned outwards. In both, however, they are 

 directed much more in the line of the ilia than 

 in the human species, the ilio -ischial angle 

 being 165; and are larger, more flattened, 

 spread, and diverging. The ischial spines in 

 these animals begin to degenerate, and are 

 rather rounded eminences or ridges than true 

 spines; and the inferior rami (/) are directed 

 almost horizontally inwards, leaving a large 

 triangular foramen obturatorium, and entering 

 into the formation of the pubic symphysis (g), 

 which in the Simice generally, may be more 

 properly called the ischio-pubic symphysis. The 

 whole of the ischial portion of the pelvis has 

 a more anterior position, and a more laterally 

 flattened appearance than in the human pelvis. 

 The cotyloid cavities are small, elongated ver- 

 tically, and deeper behind than above. The 

 sciatic notches are long and narrow. 



One of the most remarkable differences from 

 the human pelvis, however, is the difference of 

 direction of the ilia and pubes with regard to 

 the transverse-vertical plane of the spinal 

 column, an arrangement which bends the plane 

 of the pelvic brim at the ilio-pectineal eminence 

 in different directions. In the Chimpanzee, the 

 antero- posterior angle, formed by the su- 

 perior ramus of the pubis with the cotylo- 

 sacral arch of the ilium, is 120, and in the 

 Uran 125 ; constituting a striking difference 

 from the human pelvis, where the cotylo-sacral 

 and pubic arches are in one plane. 



This alteration in the direction of the pubis 

 will be found to be a great characteristic of 

 all quadrupeds, in the prone position of whose 

 bodies the pubis has a tendency to be placed 

 more vertical and more anterior, to be out 

 of the way of the femurs in their angular 

 movements. In the Sloths and Anteaters, 

 the pubis will be seen to be turned in the 

 opposite direction, yet still forming an angle 

 with the ilium, but with the retiring sides 

 turned backwards. I think, therefore, we may 

 safely take the ilio-pubic angle as a general 

 peculiarity of the inferior animals possessing 

 pelves, and one which distinguishes them, as 

 far as I have seen, universally, from the human 

 species (see page 173. fig. 112.2 13.). 



A remarkable consequence of this more 

 horizontal direction of the'pubis in the Simice is 

 the disappearance of the angle of the symphysis, 

 it being quite parallel with the spinal column. 

 And this parallel position is, according to Cu- 

 vier, a mark of distinction between all thebrute 

 creation and man. In other respects, the 

 pubis of the Simiee is short, little arched, 

 and without marked spine. The inferior 

 outlet of the pelvis is larger than it would 

 otherwise be, from the elevation of the coccyx, 

 and, from the shortness of the sacrum, and 

 length of the ischio-pubic symphysis, its plane 

 is more parallel, and its axis more in a line 

 with those of the brim than in man. 



So we see, in these animals, a marked and 



