128 
THE DESCENT OF MAN. 
Part 1. 
these it serves exclusively to aid the male in the act 
of reproduction. 
Mr. J. Wood, in his valuable series of papers , 45 has 
minutely described a vast number of muscular varia- 
tions in man, which resemble normal structures in the 
lower animals. Looking only to the muscles which 
closely resemble those regularly present in our nearest 
allies, the Quadrumana, they are too numerous to be 
here even specified. In a single male subject, having 
a strong bodily frame and well-formed skull, no less 
than seven muscular variations were observed, all of 
which plainly represented muscles proper to various 
kinds of apes. This man, for instance, had on both 
sides of his neck a true and powerful “ levator clavi - 
culde” such as is found in all kinds of apes, and which 
is said to occur in about one out of sixty human sub- 
jects . 46 Again, this man had “a special abductor of 
“ the metatarsal bone of the fifth digit, such as Pro- 
“ lessor Huxley and Mr. Flower have shewn to exist 
“ uniformly in the higher and lower apes.” * The hands 
and arms of man are eminently characteristic structures, 
but their muscles are extremely liable to vary, so as to 
resemble the corresponding muscles in the lower ani- 
mals . 47 Such resemblances are either complete and per- 
45 These papers deserve careful study by any one who desires to 
learn how frequently our muscles vary, and in varying come to re- 
semble those of the Quadrumana. The following references relate to 
the few points touched on in my text : vol. xiv. 1865, p. 379-384; vol. 
xv. 1866, p. 241, 242 ; vol. xv. 1867, p. 544; vol. xvi. 1868, p. 524. I 
may here add that Dr. Murie and Mr. St. George Mivart have shewn 
in their Memoir on the Lemuroidea (‘ Transact. Zoolog. Soc.’ vol. vii. 
1869, p. 96), how extraordinarily variable some of the muscles are in 
these animals, the lowest members of the Primates. Gradations, also, 
in the muscles leading to structures found in animals still lower in 
the scale, are numerous in the Lemuroidea. 
46 Prof. Macalister in ‘ Proc. E. Irish Academy,’ vol. x. 1868, p. 124. 
47 Prof. Macalister (ibid. p. 121) has tabulated his observations, and 
finds that muscular abnormalities are most frequent in the forearms, 
secondly in the face, thirdly in the foot, &c. 
