VARIATION AND HEREDITY 131 



admirable Evolutionary Exhibition of the 

 British (Natural History) Museum. When 

 the peculiar "waltzing ml^e" are 

 wi| f h 



The 



But when the offspring are inbred, their 

 (F s ) are normal mice and waltzing 

 prnportlIL^fJllJ^ The reces- 



n 



sive waltzers of this generation might be 

 sold as pure waltzers; with others of their 

 kind they will produce only waltzers for as 

 many generations as one likes to breed them. 

 But the normals of the same generation turn 

 out to be of two kinds though they are all 

 alike in appearance : jone- third of them_(j)ure 

 dominant?) wiliyjfM only 



(imvu-Tf. rfirm?'rmr?f Q } wiH- 

 split TigLagain, when inbred, into normal mice 

 and waltzing mice in the old proportions of 

 3:1. Another form of the scheme may be 

 used : 



p 



Pi 



'ID : .2D(R) : IB 



1D:2D(R):1 



-'D D ID i2D(R) :.1B 



