DIMINUTION OF TH-E JA WS. 



at the College of Surgeons turned out to be 

 less than a fifth of an ounce, or about 

 5 per cent. This slight reduction may be 

 much more than accounted for by such causes 

 as disuse in the individual, human preference 

 setting back the teeth, and partial transference 

 of the much more marked diminution seen in 

 female jaws. There is apparently no room for 

 accumulated inherited effects of ancestral disuse. 

 The number of jaws is small, indeed ; but weigh- 

 ing them is at least more decisive than Mr. 

 Spencer's mere inspection. 



The differences between Anglo-Saxon male 

 jaws and Australian and Tasmanian jaws are 

 most easily explained as effects of human pre- 

 ference and natural selection. We can hardly 

 suppose that disuse would maintain or develop 

 the projecting chin, increase its perpendicular 

 height till the jaw is deepest and strongest at 

 its extremity, evolve a side flange, and enlarge 



