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 panniculus 
carnosus (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’. 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. 
2G. Schwalbe, ‘‘Das Darwin’sche Spitzohr beim menschlichen Embryo,” Anatom. 
Anzeiger, 1889, pp. 176—189, and other papers. 
