MR. ST. G. MIVART ON THE SKELETON OF THE PRIMATES. 179 
clavicle decidedly exceeds one-fourth of the length of the spine (as measured from the 
atlas to the coccygeal end of the sacrum), while in Man and Zroglodytes it always, as 
far as I have observed, falls short of that proportion. The clavicle of the Orang also 
more nearly equals the length of the scapula than in the higher forms’. 
Its curvature is very slight, much less than in Man and the Chimpanzee, and less 
also than that which often exists in the Gorilla. 'The sternal curve, convex forwards, 
is very much more extensive than is the backwardly convex curvature of the outer 
or acromial part’. The acromial end bends decidedly somewhat downwards. The 
curvature does not appear to be greater in young than in old individuals®, nor in 
small adult specimens as compared with larger ones (Pl. XX XVII. figs. 3, 4). 
The two extremities of the bone are more or less flattened, the sternal articular 
surface being generally long and narrow, compared with the form it presents in Man and 
Troglodytes. ‘The long axis of this surface is sometimes nearly parallel with the greatest 
diameter of the acromial end of the bone. 
The clavicle of Simia may be described as presenting three surfaces and three 
margins. Of these, the first or superior and the second or more or less anterior one 
extend the whole length of the bone; but the third or inferior surface does not reach 
to the sternal extremity of the clavicle, being replaced by an extension of the second 
or more or less anterior surface, which here assumes a nearly inferior position. 
The first or superior surface is smooth and pretty well marked off (along its posterior 
margin) from the third or inferior surface by a ridge continued inwards from the 
tubercle for the conoid ligament, but which does not attain the sternal end of the bone, 
where the first surface is separated behind from the second one by the strong ridge for 
the rhomboid ligament. It is separated, towards the acromial end of the clavicle, 
from the second or more or less anterior surface by a very strong and rough ridge 
(Pl. XX XVII. figs. 1 & 2d) for the deltoid*; but towards the sternal end of the 
bone a slight one (for the attachment of the pectoralis major*) serves as the line 
of demarcation between the first and second surfaces in front. 
The second, a more or less anterior surface, is wide and concave towards the acromial 
end of the bone, where it is limited above by the very prominent and rough ridge for 
the deltoid before mentioned, and below by the anterior boundary of the third or 
inferior surface; towards the sternal end of the bone this surface becomes rather infe- 
1 De Blainville has found it to exceed the scapula in length (Ostéographie, “ Primates: Pithecus,” p. 30). 
* Archives du Mus. t. viii. p. 25. 
3 As shown in the immature specimen No. 3H, in the osteological collection of the British Museum. 
* Judging from the representation given by Professor G. Sandifort in his treatise on the anatomy of the 
Orang Outang, in ‘ Verhandelingen over de Natuurlijke Geschiedenis der Nederlandsche overzeesche bezittingen,’ 
Leyden, 1840, p. 48, and tab. 3. fig. 2C; also from that of Cuvier in the ‘ Recueil de Planches de Myologie,’ 
pl. 15. fig. 2%. 
5 Mr. W. S. Church describes part of the pectoralis major as arising from the clavicle in the Orang (Nat. 
Hist. Review, vol. i. p.513). Cuvier also so represents it (Recueil de Planches de Myologie, pl. 15. fig. 27). 
Pa (ohir 
