xxii CONTENTS 



CHAPTER XXVI 

 Reproduction in Animals 



PAGB 



Reproduction 292 



Spontaneous Generation 292 



Budding 293 



Fiijsion 294 



Results of Asexual Reproduction 295 



Regeneration 295 



Regeneration in Higher Animals 296 



Sexual Reproduction 297 



The Sex Cells 297 



Accessory Sex Organs 298 



Fertilization 299 



Results of Fertilization 299 



Individuality of the Chromosomes 300 



Fertilization of Unicellular Animals 301 



Early Development 302 



The Gastrula and Body Layers 302 



Later Development 303 



Vertebrate Development 304 



Growth 305 



Differentiation 305 



Metamorphosis 306 



Care of Eggs 306 



Nourishment of the Young 308 



Secondary Sexual Characters 308 



Body and Germ Cells 309 



Early History of Germ Cells 310 



Reducing Division 310 



Random Assortment of Chromosomes 311 



Maturation of the Egg 313 



Determination of Sex 313 



CHAPTER XXVII 

 Reproduction in Plants 



Sexual and .Vsexual Reproduction 316 



Typeji of Reproduction in Plants 316 



Asexual Reproduction in the Algro 317 



Essentials of Asexual Reproduction 322 



Sexual Reproduction by me^ms of Gametes 324 



The DifForentiation of Sex 327 



Alternation of Generations 327 



An Extra Generation 329 



Gamotophyte and Sporophyte 330 



Ferns 330 



The Structure of Ferns 330 



Heterospory 332 



Reproduction by Seed 334 



The Ovule and Female Gametophyte 336 



The Anthers and Male Gametophyte 337 



Fertilization, Embryo, and Endosperm 338 



