y 



Plates 6 and 7 are reproduced by permission from Publication 

 No. 2Jtl of the Carnegie Institution without change of figure num- 

 bers. They show in the natural colors how a single pure-breeding 

 domestic type {20) crossed with a single pure-breeding wild type 

 {23 and 24-) may produce in the next generation only a single type 

 {22), which Jwwever may, in the following generation, through the 

 operation of MendeVs law, produce half-a-dozen very distinct pure- 

 breeding types {25-30) . Through a knowledge of MendeVs law 

 the multiplication of color types among animals and plants has 

 ceased to be a haphazard process and has become a simple and 

 orderly procedure. 



