xii LIST OF ILLUSTRATIONS 



FIG. TAGB 



47. — ■ Diagrams to show tbe number and size of the 



classes of individuals to be expected from 

 a cross involving Mendelian segregation 

 without dominance 135 



48. — Photographs to show variation in ear length 



of two varieties of maize, of their Fi off- 

 spring, and of their Fj offspring . .Facing 138 



49. — Diagram of sex-determination in partheno- 



genesis 162 



50. — Diagram of sex determination when the female 



is homozygous, the male heterozygous . . 167 



51. — Diagram of sex-determination when the female 



is heterozygous, the male homozygous . . 170 



52. — Diagram of sex-limited inheritance when the 



female is a heterozygote 173 



53. — Diagram of sex-limited inheritance when the 



female is a homozygote, as in the red-eyed 

 Drosopbila 175 



