200 MR. ST. G. MIVAET ON THE SKELETON OF THE PBIMATES. 



The trochanteric fossa is deeper than in the Gorilla, bat, as also in Man, it is less 

 deep than in the Chimpanzee. The intertrochanteric line behind is rather more 

 sharply and strongly prominent than in any of the higher forma (PI. XL. fig. 2d). 



The head of the femur is very large, especially as compared with that of the 

 Chimpanzee, though absolutely exceeded by that of Man, and also by that of the 

 Gorilla when of large size. It is sharply defined by a prominent border all round, 

 except sometimes for a short space near the intertrochanteric fossa (PI. XL. figs. 1, 

 2, 3, 4, 6, 7«). 



The sharp projection of its anterior margin is more like what exists in Troglodytes 

 than in the general structure of Man. 



It is commonly asserted that the ligamentum teres is absent in the Orang, as also 

 the pit for its reception on the head of the femur'. I find no trace of the latter in 

 either femur of any specimen, with one exception '•' ; but in that exceptional specimen 

 each femur (PI. XL. fig. 7 i) exhibits a small but distinct depression on its head in 

 the place occupied in other forms by the pit "for the round ligament. This absence 

 has not, as far as I am aware, been noticed in Man or the Chimpanzee; but in the 

 Gorilla I have sometimes been unable to detect any trace of such a fossa on the head 

 of the femur'. It may therefore be the case that this ligament is occasionally absent 

 in the Gorilla, and occasionally present in the Orang. " 



The rotular surface (PI. XL. fig. 1 o) does not, as in Man, project higher on the 

 peroneal than on the tibial side, but more resembles in this respect that of the Gorilla 

 than even that of the Chimpanzee ; it extends, however, further up the shaft, and 

 has its superior margui more acutely convex than in Troglodutes. It is even less 

 concave transversely than in the Gorilla and Chimpanzee, and therefore still more 

 widely differs in this respect from the rotular surface of Man than do the corresponding 

 parts in them. 



The external condyloid articular surface is somewhat narrower than is the internal 

 one, but the difference is less than in Troglodytes* (PI. XL. fig. 5 m & n). 



The breadth of the intercondyloid fossa (which, as in the Gorilla, is generally 

 shallower than in Man) is about equal at its anterior and posterior ends. 



As in 'Troglodytes, the whole distal surface of the bone is broader in proportion to 

 its antero-posterior extent than in Man^, and the external xjondylc projects backwards 

 less than the internal one does — the external one being, as in that g'enus, the sliorter 

 one from before backwards, instead of rather the longer of the hvo as in Man" 

 (PI. XL. fig. bmScn). 



' Owen, Trans. Zool. Soo. vol. i. p. 36i5, and De Blainville, ' Osteographie,' Primates, Pitkeciis, p. 31. 

 - No. 3 i in the osteological collection of the British Museum. 



^ E. g. in all four femora of the specimens Nos. 5179 a and 51 79 b in the Museum of the Royal College of 

 •Siu'geons. * Owen, Trans. Zool. Soc. vol. v. p. 16, plate 7. fig. 3. 



' Owen, he. cit. p. IG, plate 7. fig. 3. ' Owen, Im: cit. p. 18. 



