XX LIST OF ILLUSTRATIONS 



FIGURE I'AGE 



77. An Armadillo Egg about Six Weeks after Fertilization, 



Showing the Quadruplet Fetuses 397 



78. Diagram Showing Chromosome Relations in Sex Determina- 



tion 399 



79. A Typical Opposite-sexed Pair of Cattle Twins .... 407 



80. Sex-Linked Inheritance of White and Red Eyes in Drosophila 41 1 



81. Recriprocal Cross TO That Shown IN Figure 80 . . . .412 



82. Sex-lin^ked Inheritance of Barred and Unbarred (Black) 



Plumage in Poultry . 413 



83. Reciprocal Cross to That Shown in Figure 82 . . . . 414 



84. Diagram Showing the Mechanism of Crossing-over . . . 422 



85. Chromosome Map of Drosophila 426 



86. Polygon of Variation for the Total Number of Scutes in 



the Nine Bands of the Armadillo 43 1 



87. Bimodal Polygon Plotted from Data on the Earwig . . . 434 



88. Correlation Table of 400 Plants of Sixty-Day Oats . . . 435 



89. Diagram of Galton's "Law of Ancestral Inheritance" . . 437 



90. Scheme to Illustrate Galton's "Law of Filial Regression" 439 



91. Oenothera lamarckiana 476 



92. A Series Showing Oenothera lamarckiana and Several of Its 



Mutants Growing Side by Side 481 



93. Diagram Showing in Condensed Form the Genealogy of the 



Oenothera lamarckiana Family and Its Various Mutants . . 486 



94. Pedigree OF A Line WITH Brachydactyly 518 



95. Inheritance of One Form of Cataract 519 



96. Pedigree Showing Heredity of Feeble-Mindedness: Family 



of Gertie K .... 521 



97. Another Pedigree Showing Heredity of Feeble-Minded- 



ness: Family of Charlie M 522 



98. Pedigree Showing Heredity OF Insanity 523 



99. Pedigree Showing Heredity of Insanity and Neurotic 



Tendency 523 



