CONTENTS. 



Page. 



Continuous versus discontinuous variations as factors in evolution .... i 



Variations of rats in coat-color and coat-pattern 4 



Mendelian inheritance of coat-colors and coat-patterns in rats 7 



Albinism recessive in relation to all types of pigmentation 7 



Latent pigment characters and coat-patterns 8 



Modification of hooded pattern by crossing with Irish 11 



Modification of hooded pattern by selection 14 



Selection for reduced stripe 14 



Selection for stripe of increased size 17 



Individual spots of guinea-pigs not unit characters 18 



Color-patterns selected 18 



Dutch-marked series (Series D) 20 



Head-spot series (Series H) 23 



Statistical analysis of the data for Series D and II 25 



Nose-spot series (Series N) 26 



Conclusions 32 



Tables 34 



Bibliography 50 



