XVI LIST OF ILLUSTRATIONS 



FIGURE TITLE PAGE 



120 Regeneration and grafting in Hydra . 221 



121 Regeneration and grafting in an Earthworm 222 



122 Regeneration and grafting in a Flatworm 223 



123 Typical stages in Mitosis 225 



124 Period of chromosome reduction in animals and plants . 229 



125 Spermatogenesis and oogenesis in animals 231 



126 Chromosome cycle in an animal 235 



127 Egg and sperm of Lamprey . 236 



128 Hen's egg 238 



129 Human egg and sperm 239 



130 Conjugation in Paramecium 245 



131 Endomixis in Paramecium 248 



132 Development of Dentalium 255 



133 Comparison of the development of Dentalium and Amphioxus 257 



134 Relation of cytoplasmic differentiation to development . 259 



135 Continuity of the germ plasm 265 



136 Alternative, mosaic, and blending inheritance .... 269 



137 Law of filial regression 270 



138 Inheritance of size in Peas 273 



139 Mendelian monohybrid 275 



140 Mendelian dihybrid 277 



141 Inheritance of human hair characters 278 



142 Possible types of zygotes in a dihybrid 279 



143 Mendelian trihybrid 281 



144 Color inheritance in the Four-o'clock (Mirabilis jalapa) . 284 



145 Color inheritance in mulattoes . . 285 



146 Chromosome cycle in an animal . . ; . . . . . 289 



147 Chromosomes or genes at fertilization and maturation . . 290 



148 The X chromosome in fertilization 293 



149 Inheritance of color-blindness from the male . . . . s . 294 



150 Inheritance of color-blindness from the female . . . . 295 



151 Crossing-over at synapsis 296 



152 Nature and nurture 298 



153 Population and pure lines in Beans . 300 



154 Model to illustrate the law of probability 301 



155 Normal frequency curve 302 



156 Selection and filial regression 303 



157 Relation of pure lines to a population 305 



158 Sulfur Bacteria (Beggiotoa) 309 



159 Yeast 310 



160 Spore formation in Bacteria 312 



161 Adaptive radiation in Eutheria,a ivlaimnals 314 



162 Gymnura ... 315 



