230 n;o( KKDIM;< OK THE ANATOMICAL AND ANTHROPOLOGK \i. 



in llii, and over 15 mm. in 126. In 563 women the results will be 

 seen to be approximately similar. For purposes of comparison it is 

 necessary to estimate what may be named the mean or index develop- 

 ment of the lobule ; this was obtained as follows : The lobule of 

 Stage 1 was taken as a unit, Stage 2 as two units, Stage 3 as three 

 ;ind Stage 4 as four, so that in the group of males at present under- 

 consideration the mean development of the lobule was : 



117 x 1 + 111 x 2 + 119 x 3 + 126 x 4 = 2 . 53 

 473 



The index for the female series is 271. That is to say, the average 

 development of the lobule in the groups I examined lay between 

 Stages 2 and 3, but it reaches a distinctly greater development in the 

 women than in the men. 



It will be observed that the number of individuals is nearly 

 equally divided among the four stages (117, 111, 119, 126), and it will 

 occur to those who are familiar with the manner in which anthropo- 

 logical data group themselves into a maximum near the mean and 

 diminish towards the extremes, that either my method is artificial or 

 inaccurate, or that the lobule is not subject to the laws that regulate 

 the development of other parts of the body. It will be noticed that 

 the observations made on the females show a similar distribution, so 

 that at least if the method is artificial it has evidently been applied in 

 M similar manner to each group. But there can be no doubt that in 

 my earlier work I placed many examples of the two intermediate 

 stages into the two extreme groups. 



The result so far obtained is that the index of development for 

 the lobule of the ear in Aberdeen men is 2'53 ; the female index is 

 greater by '18. Is there constantly a sexual difference and what is its 

 meaning '. The lobule always obtains a greater development in the 

 temale ear. The lobule represents tissue which in lower primates is 

 utilised in the formation of the lower part of the helix ; that is, it 

 represents a retrograde change in the outer ear. Its greater si/e in 

 (lie female is probably due to the fact that the outer ear of the female 

 shows more evidence of retrogression than that of the male. 



