ME. ST. G. MIVAET ON THE SKELETON OF THE PRIMATES. 179 



clavicle decidedly exceeds one-fourth of the length of the spine (as measured fi-om the 

 atlas to the coccygeal end of the sacrum), while in Man and Troglodytes 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 gi-eater in young than in old individuals^, nor in 

 small adult specimens as compared with larger ones (PI. XXXVII. 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 ofl" (along its posterior 

 margin) from the thii'd 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 

 (PI. XXXVII. figs. 1 & 2<Z) for the deltoid'^; but towards the sternal end of the 

 bone a slight one (for the attachment of the pectoralis major^) seiTes 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 tliird or 

 inferior surface ; towards the sternal end of the bone this surface becomes rather infc- 



' De Blain-s-illc has found it to exceed the scapula in length (Ostcographie, " Primates : Pithems," p. .30). 

 ^ Archives du Mus. t. viii. p. 25. 



* As shown in the immature specimen Iso. 3 H, in the osteological coUeetion 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 Gesehiedciiis der Ncdcrlandschc ovcrzccsche hezittingcn,' 

 Leyden, 1840, p. 48, and tab. 3. fig. 2C; also from that of Cuvicr in the ' Eecueil de Planches do Myologie.' 

 pi. 15. fig. 21c. 



' Mr. W. S. Church describes part of the pectoralis major as arising from the clavicle in the Orang (Xat. 

 Hist. Eeview, vol. i. p. 513). Cuvier also so represents it (Eecueil de Planches de Myologie, pi. 15. fig. 2j). 



2 C 2 



