PRIMROSE : THE ANATOMY OF THE ORANG OUTANG 
83 
original typical form, these modifications being due to a specialization 
of function — one holds this view despite the fact that Bischoff comes to 
the conclusion that both anatomically and physiologically the so-called 
posterior hand of the ape possesses more agreement with the human 
hand than with the human foot. 
No doubt certain conditions in the ape’s foot resemble the conditions 
present in the hand, and differ from those of the human foot The 
adductor transversus hallucis in the ape’s foot tends to blend with the 
adductor obliquus and is much more strongly developed than in the 
human foot. In this particular the muscle in the ape’s foot approaches 
that found in the hand of man and differs from the human foot In my 
Orang I found an opponens hallucis ; this muscle is not always found in 
anthropoids, but appears to be peculiar to the Orang, and among lower 
apes it is found in Macacus. This is a characteristic muscle of the hand 
and is not found in the human foot Among apes there is a frequent 
approach to the hand (as in my Orang), in the arrangement of the 
interossei, whereby abduction is secured from the third digit and not 
from the second. Huxley^ admits that the foot of the Orang deviates 
very greatly from that of man. The great length of the phalangeal 
portion of the foot is very noticeable, and the narrow os calcis with an 
absence of the two tubercles which are present in man. There is great 
mobility between the carpal bones ; the phalanges are greatly curved. The 
hallux is remarkably short,and is capable of extreme abduction from the 
other digits, whilst opposition is also possible to a complete degree. In 
connection with the movableness of the great toe in apes one is struck 
by the peculiarity of the shape of the articulation between the first 
metatarsal bone and the internal cuneiform. The articular surfaces are 
saddle-shaped, and thus provide for greater freedom of movement. This 
differs from the foot of man where the surfaces are flat and is in agree- 
ment with the hand of man where the characteristic saddle-shaped joint 
is found between the trapezium and the first metacarpal. This condition 
in the ape was described by Huxley in the Chimpanzee’s foot, and it 
was also noted by Huxley that, in the hand, the trapezium in that 
animal presented a simple, oval, convex facet, and was no longer saddle- 
shaped.^ In the lower apes, however, Huxley found the characteristic 
saddle shape of the trapezium.^ Fick describes this joint of the first 
digit as being saddle-shaped in both foot and hand in the Orang C Bis- 
1 Loc. cit., Vol. I, p. 564. 
2 Loc. cit., Vol, I, p. 428. 
3 Loc. cit., Vol. I, p. 671. 
4 Loc. cit. I, p. 50. 
