viii                                    Contents
 

CHAPTER  VI

PAGE

Experimental Hybridizing.........66

Mendel's Law...........66

Mendel's Law and the Germ-cells         .......      72

CHAPTER  VII

Experimental Hybridizing {Continued)           .       .       .       .       .       .82

Experiments with Mice          .........      82

CHAPTER  VIII

Experiments with other Mammals and with Birds  ....     99

Experiments with Guinea Pigs      ........      99

Experiments with Rabbits     .........    106

Experiments with Rats          .        .        ,        .        .        .        .        .        .110

Experiments with Cats .        .        .        .        .        .        .        .        .        -113

Data for Other Mammals and Man       .        .        .        .        .        .        .116

Experiments with Poultry     .........    121

Experiments with Pigeons.........135

CHAPTER  IX

Experiments with Snails, Moths, and Beetles.....139

Experiments with Silkworms         ........    141

Experiments with Beetles      .        .        .        .        .        .        .        .        -ISI

Experiments with the Currant Moth      .        .        .        .        .        .        -153

Experiments with Tephrosia.......        -153

CHAPTER X

Other Kinds of Hybridizing........156

Blended Inheritance..........156

Mosaic Inheritance        ..........    157

Hybridization between Linnaean Species       .        .        .        .        .        .157

Dimorphism          .        .        .        .        .        .        .        .        .        .        .160

Reversal of Symmetry   ..........    165

Conclusions regarding Mendelian Inheritance       .        .        .        .        .166

CHAPTER XI
Behavior of the Germ-cells in Cross-fertilization .       .       ,       •    '^IZ

173

175
178
181
182
 

Experiments with Amphibia          .....

Experiments with Echinoderms     .....
Factors involved in the Entrance of the Spermatozoon
Artificial Helps to Fertilization and to Cross-fertilization
Polyspermy   .........