1898-99. | THE ANATOMY OF THE ORANG OUTANG. 577 
Gratiolet and Alix! differed from Hepburn regarding the Chimpanzee, 
as they found abduction was from a line drawn through the third digit. 
Thus, there is apparently some variation among the anthropoid apes, 
but the most common arrangement is abduction from a line through the 
third digit, and this, as far as my observation has extended, has 
always been found to be the case in the Orang, excepting in: Fick’s 
example mentioned above. 
Attention has already been directed to the fact that the foot of the 
Orang resembles, in outward appearance, the human hand rather than 
the human foot. This observation led naturalists to apply the term 
“quadrumanous” to those apes possessing such characteristics. The 
external characters of the foot of the Orang certainly suggest a hand 
rather thana foot. Further, the foot of the Orang differs very materially 
in its external characters from that of man (compare the photographs of 
the hand and foot of man with those of the Orang). In considering the 
question as to whether the posterior extremity of the Orang possesses a 
hand or a foot, we must constantly have in mind the characteristic fea- 
tures of the human hand and the human foot with which to institute 
comparisons. It is not necessary to discuss at length the correspond- 
ences which are found in comparing the hand with the foot, but certain 
of the more obvious of these may be alluded to, and one is greatly aided 
in thus establishing homologies in man by reference to the lower ani- 
mals. In the hand we have five digits as in the foot, and we find that 
the bones of the fingers and toes, z.e., the metatarsals and metacarpals, 
with the phalanges, correspond in number, and have sufficient individual 
resemblances to make it an easy task to recognize those bones of the 
hand which correspond to similar ones in the foot. The carpal and 
tarsal bones are not so readily distinguished, but by referring both series 
of bones to a less specialized type of carpus and tarsus, one is able to 
establish very readily a series of probable homologies. The carpus or 
tarsus of the water tortoise has been suggested by Gegenbaur and Oscar 
Schmidt? for this purpose, and by referring the bones of the foot and 
hand to this simple form, we can determine the corresponding struc- 
tures. In the following table, taken from Quain’s Anatomy,’ an 
attempt is made to establish these homologies. The “typical-names” 
here employed refer to the bones'in the carpus or tarsus of such a gen- 
eralized formas the water tortoise :— 
1 Loe. cit., p, 190. : 
‘2 Oscar Schmidt. ‘‘ The Mammalia in their Relation to Primeval Times.” London, 1895, p. 36. 
3 Vol. II, Part I, p. 144. 
