ILLUSTRATIONS xiii 



FIG. I'AdE 



28. Scheme of Cross between Red-Eyed Male Dro- 



sophila and White-Eyed Female . . , 100 



29. Diagram of Chromosomes in Proienor . . 102 



30. Chromosomes of Z)r<9J^//^z7a . . . .104 



31. Figure illustrating Cross between White-Eyed Male 



Drosophila and Red-Eyed Female . . . 105 



32. Figure illustrating Cross between White - Eyed 



Female Drosophila and Red-Eyed Male . . 107 



33. Chromosomes of Abnormal Female Drosophiin . 109 



34. Scheme illustrating Cross between Black Tom 



Cat and Yellow Female . . . . 1 10 



35. Scheme illustrating Cross between Yellow Tom 



Cat and Black Female . . . . • iio 



36. Pedigree of Colour-blinds . . . . .111 

 37.. Scheme of Inheritance for Silver Hen . . . 113 



38. Normal Sterile X Cretin Fertile Sweet-Pea . . 115 



39. Scheme illustrating Distribution of Chromosomes . 135 



40. Diagram illustrating Linear Arrangement of 



Chromosomes in /^r^j-^/////^ . . . . 13S 



41. Drosophila-, Black Vestigial x Grey Normal •. 139 



42. Diagram illustrating "Crossing Over" . . 143 



43. Drosophila] Black Normal x Grey Vestigial . 145 



44. Single and Double Stocks . . . . .154 



45. F2 Generation ex Silky Hen x Brown Leghorn 



Cock 160 



46. Graphic Representation of Weight Distribution in 



Fj and F.2 Generations from Sebright-Hamburgh 



Cross . . . . • • • .165 



