- }2ARE THE EFFECTS OF USE INHERITED? 



sexual selection and to panmixia under male 

 protection. 



I think, on the whole, we must conclude that 

 the human jaws do not afford satisfactory proof 

 of the inheritance of the effects of use and disuse, 

 inasmuch as the differences in their weight and 

 shape and size can be more reasonably and con- 

 sistently accounted for as the result of less 

 disputable causes. 



DIMINISHED BITING MUSCLES OF LAP-DOGS. 



The next example, the reduced biting muscles, 

 &c., of lap-dogs is also unsatisfactory as a proof 

 of the inheritance of the effects of disuse ; for 

 the change can readily be accounted for without 

 the introduction of such a factor. The previous 

 natural selection of strong jaws and teeth and 

 muscles is reversed. The conscious or unconscious 

 selection of lap-dogs with the least tendency to 



