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 Quaclrumana, 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- 

 cular" 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- 

 " fessor 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 resemble those 

 of the Quadrumana. The following references relate to the few points 

 touched on in my text : Proc. Eoyal Soc. vol. xiv. 1805, 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. R. 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. 



