Man and the Lower Animals 117 



discussion of sexual selection in relation to man, and a general 

 summary. Part II treats of sexual selection in general, and may be 

 disregarded in our present study. Moreover, many interesting details 

 must necessarily be passed over in what follows, for want of space. 



The first part of the Descent of Man begins with an enumeration 

 of the proofs of the animal descent of man taken from the structure 

 of the human body. Darwin chiefly emphasises the fact that the 

 human body consists of the same organs and of the same tissues as 

 those of the other mammals ; he shows also that man is subject to the 

 same diseases and tormented by the same parasites as the apes. He 

 further dwells on the general agreement exhibited by young, em- 

 bryonic forms, and he illustrates this by two figures placed one 

 above the other, one representing a human embryo, after Ecker, the 

 other a dog embryo, after Bischoff \ 



Darwin finds further proofs of the animal origin of man in the 

 reduced structures, in themselves extremely variable, which are 

 either absolutely useless to their possessors, or of so little use that 

 they could never have developed under existing conditions. Of such 

 vestiges he enumerates : the defective development of the pannicvlus 

 camosus (muscle of the skin) so widely distributed among mammals, 

 the ear-muscles, the occasional persistence of the animal ear-point in 

 man, the rudimentary nictitating membrane (plica semilunaris) in 

 the human eye, the slight development of the organ of smell, the 

 general hairiness of the human body, the frequently defective develop- 

 ment or entire absence of the third molar (the wisdom tooth), the 

 vermiform appendix, the occasional reappearance of a bony canal 

 (foramen supracondyloideum) at the lower end of the humerus, the 

 rudimentary tail of man (the so-called taillessness), and so on. Of 

 these rudimentary structures the occasional occurrence of the animal 

 ear-point in man is most fully discussed. Darwin's attention was 

 called to this interesting structure by the sculptor Woolner. He 

 figures such a case observed in man, and also the head of an 

 alleged orang-foetus, the photograph of which he received from 

 Nitsche. 



Darwin's interpretation of Woolner's case as having arisen through 

 a folding over of the free edge of a pointed ear has been fully borne 

 out by my investigations on the external ear 2 . In particular, it was 

 established by these investigations that the human foetus, about the 

 middle of its embryonic life, possesses a pointed ear somewhat 

 similar to that of the monkey genus Macacus. One of Darwin's 

 statements in regard to the head of the orang-foetus must be 



1 Descent of Man (Popular Edit., 1901), fig. 1, p. 14. 



2 G. Schwalbe, "Das Darwin'sche Spitzohr beim menschlichen Embryo," Anatom. 

 Anzeiger, 1889, pp. 176 — 189, and other papers. 



