xiv List of Illustrations 



FIGURE PAGE 



15. Diagram of F 2 showing ratio 9:3:4 . . . . 77 



1 6. Diagram of F 2 showing ratio 9:7 89 



17. Diagram of F 2 in Sweet Pea showing ratio 27:9:28 . 91 



1 8. Pedigrees of eye-colour in Man 108 



19. Pollen grains of Sweet Peas . . .150 



20. Heredity of horns in Sheep . .171 



21. Heredity of a peculiar form of curly hair . 207 

 '22. Descent of congenital lock of white hair . .207 



23. Brachydactylous hands ... .211 



24. Skiagram of hands .... 212 



25. Hands of brachydactylous child . 213 



26. Pedigree of brachydactylous family . .214 



27. Descent from brachydactylous members 214 



28. Drinkwater's pedigree of brachydactyly . 215 



29. Descent of prae-senile cataract . 216 



30. Another cataractous family ... 217 



31. Descent of stationary night-blindness . between pp. 220-221 



32. Descent of Colour-blindness . . . . . . 223 



33. Ideal Scheme of descent of simple sex-limited condition, 



e.g. horns of Sheep 230 



34. Tentative representation of descent of Colour-blindness . 231 



35. Polish x Rivet Wheat .259 



36. Seeds of Polish x Rivet Wheat . .260 



37. Reversion in height of Sweet Peas . . 282 



38. Two types of dwarf Sweet Peas 283 



