ME. ST. G. MIVART ON THE SKELETON OF THE PRIMATES. 213 



from that existing in the superior forms, the former only being about four-fifths tlic 

 length of the latter, instead of much exceeding it, as in Man and Trofflodi/tes. 



The proportion borne by the whole index of the pes to that of the manus is greater than 

 that existing in the higher forms, the former being almost quite as long as the latter. 



The difference between the length of the index and that of the haUux is vastly 

 greater than that in Man or Troglodytes. 



The fifth digit is the shortest, not counting the hallux ; the second is somewhat 

 longer, then the fourth, and the third is the longest (PI. XLIII. fig. 1). The order of 

 projection is similar to that of length. 



The proportion borne by the longest digit (without its metatarsal) to the longest meta- 

 tarsal, is greater than in Troglodytes, and of course very much greater than in Man. 



The haUux only reaches as far forwards as fi-om three-fourths to five-sixths of the 

 length of the metatarsal of the index ; and therefore the Orang differs fi-om Man and 

 Troglodytes in that its hallux does not reach so far forwards in relation to the contiguous 

 digit as does its poUex, while in them the hallux, thus estimated, extends further 

 forwards than does the pollex". 



The appendicular skeleton otSimia, while in some respects it more nearly resembles that 

 of Man than does the corresponding structure in Troglodytes, yet on the whole departs 

 further from the human skeleton than does that of the Chimpanzee, or that of the Gorilla. 

 This divergence is most marked in the extremities ; and the small differentiation of the 

 bony structm-e of the terminal limb-segments of the Orang is especially remarkable. 



In addition to the various resemblances and differences offered by the limb-bones of 

 Simia to the same parts in Homo and Troglodytes, I find that the Orang, when com- 

 pared with all the species of the order Primates ^ presents the following more or less 

 noteworthy conditions : — 



The proportion borne by the pectoral limb to the spine is greater than in any otlier 

 genus except Tarsius and Ilyhhates. 



The proportion of the length of the radius to that of the spine is greater than in any 

 other except Hylohates. 



The length of the index, with its metacarpal, compared with the spine, is greater 

 than in any except Tarsius and Hylohates. 



The length of the metacarpal of the poUex is greater, in proportion to that of the 

 spine, than in any other except Hylohates and Tarsius. 



The spine of the ischium is more largely developed than in any other Primate 

 except Man. 



' See Huxley and Hawkins, 'Atlas of Comparative Osteology,' plate x. figs. 1, 2 & 3, and plate xii. figs. 

 1 0, 2a, .3a, & 4« ; also Dr. Lucae's paper before referred to, plate iii. figs. 2, 5 & !>, plate ii. fig. 5, plate i. 

 fig. 2, and plate iv. figs. 1, 5 ik 6. 



' See a paper " On the Skeleton of the Primates," communicated to the Royal Society on November 22, 

 1866, read on January 10, 1867, and to be published in the 'Philosophical Transactions,' vol. dvii. (ISflT) 

 p. 299, plates xi.-xiv. 



