Macaltster — On the Muscular Anatomy of the Gorilla. 503 
XXIX., Pig. 1) large and distinct, and I found the same in one of the 
chimpanzees. The flexor carpi radialis is larger than in the chim- 
panzee. The palmaris longus showed what is not an uncommon human 
anomaly, viz. : — a flat tendinous origin, an intermediate belly and a 
round tendon of insertion. This was only an individual variation, as 
the normal palmaris has been found in other gorillas. I found the 
same variety in one chimpanzee. The palmaris was rather larger in 
the chimpanzee than in the gorilla. 
The flexor carpi ulnaris had its usual heads, which speedily united ; 
it was one third larger than the radial flexor, while in the chimpan- 
zees they were absolutely equal in three of the four forearms dissected 
(in the right arm of the first chimpanzee I found the flexor carpi 
radiali a little larger than the flexor ulnaris). The flexor digitorum 
sublimis had a radial as well as a condyloid origin, and equalled the 
combined radial and ulnar carpal flexors ; this radial origin is large in 
one of the chimpanzees, but absent in the other. In one there was no 
tendon to the little finger, as in Moore's chimpanzee. This muscle is 
twice as large in the gorilla as in the chimpanzee. 
The flexor profundus digitorum, a large muscle, was double the last 
in weight, and it sent no tendon to the poUex ; in it were easily discri- 
minable the germs of the flexor pollicis longus, and of the flexor pro- 
fundus digitorum. In the chimpanzees it sent ofl" a fine silky tendon 
to the pollex, and the two muscles were more separable though their 
tendons were combined. The flexor pollicis mainly supplied the index 
in the gorilla. 
Unconnected with the last muscle, there arose from the fascia over 
the OS magnum and over the trapezium in both hands a flat tendon, 
which narrowing was attached by one slip to the base of the first 
phalanx, and by a final expansion into the base of the second phalanx of 
the pollex; this was evidently the true flexor pollicis longus tendon, 
and it lay in the inter-space between the two polliceal sesamoid bones. 
The pronator quadratus was very small, extending for one-fourth 
of the forearm, even smaller than in the chimpanzee. The supinator 
longus is moderate, double the combined pronators, and its tendon was 
split by the radial nerve. In the chimpanzee it is smaller, not being 
equal to the pronators ; its insertion was as in man, in the gorilla, but 
on a plane higher, as in the chimpanzee. 
The extensor carpi radialis longior is one-half the weight of the 
brevier. In the chimpanzee they are barely equal, the supinator 
brevis is one-third the size of the s. longus, yet not quite so large in 
the gorilla as in the chimpanzee. The extensor digitorum communis 
is inserted mainly into the second, third, and fourth fingers, and by a 
very little slip into the fifth ; in size it is half that of the flexor sub- 
limis digitorum. The extensor minimi digiti is not only attached to 
that digit as in the chimpanzees, but by a very slender slip to the 
fourth; this muscle is one-fourth of the last in the gorilla, only one- 
sixth in the chimpanzee. The extensor carpi ulnaris is larger than in 
