332 ME. ST. GEOEGE MIYAET ON THE SKELETON OE THE PEI MATES. 
times in Cynocephalus the proportion is as 97 to 100, and it varies between this and 
55 to 100, except in Arctocebus and Nycticebus, where the breadth is but very little! 
above half the length, and in Loris, where it is even less than half. 
The length of the os innominatum, compared with that of the scapula (measured from - 
the anterior end, or summit of the glenoid surface to the posterior vertebral angle), is 
greatest in the Chimpanzee and some other Simiidse, and is least in Man, the Orang 
and lower Cebidte, Galago, Tarsius, Nycticebus, and Hapale. 
The crest of the ilium undergoes a great change in form and proportion as we pass 
from one end to the other of the ordinal series. 
Its length (measured along its curves) never equals half that of the os innominatum, 
except in Man and the Simiinse ; and, indeed, in Hylobates this is only sometimes the 
case. In Man alone does it nearly equal (and sometimes exceed) the length of the! 
entire bone. It is at its minimum in Galago and the Nycticebinae. 
The breadth of the ilium, as measured by a straight line joining the points corre- 
sponding with the superior spinous processes of Man, exceeds half the total length of the 
os innominatum only in Man, the Gorilla, and the Orang, being respectively, to the latter 
dimension at 100, about as 69’8, 50’8, and 50*7 respectively. 
The crest of the ilium is in some few forms much arched in a direction corresponding 
with that which is upwards in Man. This is especially the case in Hylobates, Mycetes, 
Ateles, and Lagothrix, and in a less degree generally in Man, .Troglodytes, and Simia. 
In the other Anthropoidea it is but little so arched, the curve of the crest of the ilium 
being to a straight line joining its extremities as 126'4 to 100 on an average. In Indris 
and Lemur it is sometimes very slightly more arched ; but in Galago, the Nycticebinae, 
and Tarsius it is almost straight. 
The lateral (in Man horizontal) curvature of the crest of the ilium presents a strongly- 
marked sigmoid flexure in none but Man, though in Troglodytes, and sometimes in 
Simia, there is a slight trace of such sigmoid curvature. 
In the rest of the order the margin is all but, or quite straight, as in the Nycticebinae ; 
or there is but one lateral curve concave outwards, and this curvature is carried to its 
maximum in Ateles and Lagothrix (Plate XIII. fig. 1). 
The crest of the ilium is generally thin, but more or less thickened at the points 
corresponding with the superior spinous processes of Man ; in him alone, however, is it 
thickened at a point some distance behind the anterior superior spinous process, a 
thickened tract extending thence downwards to the acetabulum. In the lower Simiidae 
(which have short iliac crests compared to those of Simiinse) these crests are generally 
thicker relatively than in the latter. In the Cebidse they are somewhat thinner, but the 
thickening at the ends is much marked in most Lemuroidea, though in the Nycticebinse 
the very short crests are almost uniformly, as well as considerably, thickened. 
The ventral (or anterior) margin of the ilium in Man is very short, but it is generally 
elongated and straight, or very slightly concave. It is, however, sometimes strongly 
concave in Troglodytes and Simia, still more so in Indris (Plate XIII. fig. 2), and 
