14 THE DESCENT OP MAN. 



least in function. I have seen one man who could draw the whole 

 ear forwards; other men can draw it upwards; an- 

 other who could draw it backwards;-' and from what 

 one of these persons told me, it is probable that most of us, by 

 often touching our ears, and thus directing our attention towards 

 them, could recover some power of movement by repeated trials. 

 The power of erecting and directing the shell of the ears to the 

 various points of the compass, is no doubt of the highest service 

 to many animals, as they thus perceive the direction of danger; 

 but I have never heard, on sufficient evidence, of a man who pos- 

 sessed this power, the one which might be of use to him. The 

 whole external shell may be considered a rudiment, together with 

 the various folds and prominences (helix and anti-helix, tragus 

 and anti-tragus, &c.) which in the lower animals strengthen 

 and support the ear when erect, without adding much to its 

 weight. Some authors, however, suppose that the cartilage of the 

 shell serves to transmit vibrations to the acoustic nerve; but Mr. 

 Toynbee,^'' after collecting all the known evidence on this head, 

 concludes that the external shell is of no distinct use. The ears 

 of the chimpanzee and orang are curiously like those of man, 

 and the proper muscles are likewise but very slightly developed.™ 

 I am also assured by the keepers in the Zoological Gardens that 

 these animals never move or erect their ears; so that they are 

 in an equally rudimentary condition with those of man, as far as 

 function is concerned. Why these animals, as well as the pro- 

 genitors of man, should have lost the power of erecting their 

 ears, we cannot say. It may be, though I am not satisfied with 

 this view, that owing to their arboreal habits and great strength 

 they were but little exposed to danger, and so during a lengthened 

 period moved their ears but little, and thus gradually lost the 

 power of moving them. This would be a parallel case with that 

 of those large and heavy birds, which, from inhabiting oceanic 

 islands, have not been exposed to the attacks of beasts of prey, 

 and have consequently lost the power of using their wings for 

 flight. The Inability to move the ears in man and several apes 

 is, however, partly compensated by the freedom with which they 

 can move the head in a horizontal plane, so as to catch sounds 

 from all directions. It has been asserted that the ear of man alone 



^ Canestrini quotes Hyrtl. ('Annuarle della Soc. del Naturalist!,' Mo- 

 dena, 1867, p. 97) to the same effect. 



'" 'The Diseases of the Ear," by J. Toynbee, P. R. S., 1S60, p- 12. A 

 distinguished physiologist. Prof. Preyer, informs me that he had lately 

 been experimenting- on the function of the shell of the ear, and has 

 come to nearly the same conclusion as that given here. 



™ Prof . A. Maoalister, 'Annals and Mag. of Nat. History,' vol. vii. 

 1871, p. 342. 



