330 
ME. ST. GEOEGE MIYAET ON THE SKELETON OF THE PEIMATES. 
In absolute size this bone attains its maximum in the Gorilla * ; it is next longest in 
the Chimpanzee, then in the Orang, afterwards in Man, and then in the largest Cyno- 
cephali ; and there is even less difference in its length between the last and Man than 
there is between Man and the Gorilla. 
The expansion of the ilium, as measured by the length of its crest, is again greatest in 
the Gorilla, and then in Man, who in this respect exceeds both the Chimpanzee and 
Orang. The Siamang follows these, and close upon it the Mandrill. 
The part corresponding with the anterior margin of Man is longer than in him in all 
the largest Simiidse, and sometimes in Ateles. 
The pubic symphysis is actually longest in some Cynocephali, then in Troglodytes, 
Simia, and Man. 
The conjugate diameter of the pelvis j’ is far greatest in the Gorilla, then in the 
Chimpanzee, Man, and the Orang. 
Its transverse diameter is also greatest in the Gorilla. 
The ilio-pubic angle, or that angle formed by the iliac part of the ilio-pectineal line 
with the anterior (in Man superior) margin of the so-called “ horizontal ” ramus of the 
pubis, varies from 88°, or even somewhat lessj, in Loris to 180 in Man. 
That ilio-ischial angle formed by the superior part of the ilio-pectineal line with the 
superior (in Man posterior) margin of the ischium, is about 110° or 113° in Man; but 
in Apes and Lemuroids it varies from 140° to more than 180°, as also in some Cebidse. 
The angle formed by the same part of the ischium with the superior (in Man posterior) 
margin of the ilium is in Man about 140°, in Hylobates about 147°; in the rest it varies 
between this and 180°, which it attains in Troglodytes and Loris, but in Cynocephalus 
and some Cebidse it is yet greater. 
The extreme length of the os innominatum, when compared with that of the spine, is 
greatest in the Gorilla, where the former is decidedly more than one-half of the latter. It 
is also rather more than half in the Chimpanzee. In the Orang the proportions are as 
45*8 to 100 ; in Hylobates, Ateles, Tarsius, Cynocephalus, and Lagothrix from 43*5 to 
36*7 ; in Man and Cebus 32; the rest vary between this and 25, except Nyctipi- 
thecus, Callithrix, and Arctocebus, in which this bone is a trifle less than a quarter of 
the length of the spine. 
The length of the inferior (in Man anterior) margin of the ilium between the spinous 
processes, compared with the length of the spine, is greatest in Tarsius and the Chim- 
panzee, where it is over one-fifth ; the rest vary between this and Man, in whom it is 
considerably less than one-tenth. 
Comparing the same margin with the total length of the os innominatum, the pro- 
* Professor Owen remarks that it “ would fit a human giant ten feet in height.” Trans. Zool. Soc. vol. v. p. 12. 
t Measured from the caudal end of the ventral surface of the first sacral vertebra to the symphysis pubis. 
t Mr. John Wood, in his admirable article on the Pelvis in Todd’s 1 Cyclopaedia of Anatomy and Physiology,’ 
vol. v., gives 75° as the ilio-pubic angle of Loris. He calls attention to the great peculiarity in Man of the 
ilio-pubic angle being represented by a straight line. 
