32 THE DESCENT OF MAN 



whole external shell may be considered a rudiment, together 

 with the various folds and prominences (helix and anti- 

 helix, tragus and anti- tragus, etc.) which in the lower ani- 

 mals strengthen and support the ear when erect, without 

 adding much to its weight. Some authors, however, sup- 

 pose that the cartilage of the shell serves to 'transmit vibra- 

 tions to the acoustic nerve; but Mr. Toynbee,"" after collect- 

 ing all the known evidence on this head, concludes that the 

 external shell is of no distinct use. The ears of the chim- 

 panzee 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 oars; 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 progenitors 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 possesses a lobule; but "a rudi- 

 ment of it is found in the gorilla";" and, as I hear from 

 Prof. Preyer, it is not rarely absent in the negro. 



29 "The Diseases of the Ear," by J. Toynbee, F.R.S., 1860, p. 12. A dis- 

 tinguished physiologist, Prof. Preyer, informs me that he had lately been ex- 

 perimenting on the function of the shell of the ear, and has come to nearly the 

 same conclusion as that given here. 



3» Prof. A. Macalister, "Annals and Mag. of Nat. History," vol. vii., 

 1811, p. 342. 



s' Mr. St. George Mivart, "Elementary Anatomy," 1873, p. 396. 



