1898-99. ] THE ANATOMY OF THE ORANG OUTANG. 579 
analogues and homologues for other muscles, the movements of prona- 
tion and supination in the forearm must be regarded as being performed 
by muscles which have no homologues in the leg. The suggestion of 
“Melzer (see p. 567 of this paper), deserves mention in this connection. 
He regards the humeral head of the pronator radii teres as being repre- 
sented by the external head of the gastrocnemius, whilst the ulnar head, 
he claims, is represented by the popliteus. I, however, accept Huxley’s 
view as the correct one and look upon the pronator radii teres of the 
forearm as the homologue of the popliteus in the leg. Melzer’s view is 
not tenable; there is good reason to look upon the gastrocnemius 
muscle as representing the flexor carpi radialis and the flexor carpi 
ulnaris of the forearm. 
Huxley! asserts that the foot of man is distinguished from his hand 
by the following absolute anatomical differences : 
1. By the arrangement of the tarsal bones. 
2. By having a short flexor and a short extensor muscle of the 
digits. 
3. By possessing the muscle termed peroneus longus. 
Bischoff? questions the correctness of Huxley’s assertion. He con- 
siders that both peronei muscles together form a muscle which has 
become doubled in the foot and represents, as we have stated, the single 
extensor carpi ulnaris in the hand. In similar fashion he considers that 
the single muscle which we describe as the tibialis anticus in the foot is 
doubled in the hand, being there represented by the extensores carpi 
radialis longior et brevior. Huxley, however, has shown conclusively 
that the tibialis anticus corresponds to the extensor ossis metacarpi 
pollicis (abductor longus pollicis). There can be no doubt of this ; the 
former is inserted into the first metatarsal bone and the internal cunei- 
form, whilst the latter is inserted into the first metacarpal bone and the 
trapezium. 
The distinctive difference which Huxley claims for the foot 
in possessing the short extensor and the short flexor is denied by 
Bischoff, who concludes that if we contrast these muscles with the 
tendons which we describe under the terms “ perforans” and “ perfor- 
atus” in the hand, we shall find homologous structures, but we may go 
further, and we find it easy to produce evidence to lead us to the 
1 Huxley, ‘‘ Evidences as to Man’s Place in Nature,’ New York. 1890, p. 107. 
2 Loc. cit. 1, p. 236-7. 
