CONTENTS 



4 RESPONSIVENESS IN VERTEBRATES 86 



ORGAN SVSIEMS RELAIKU TO fXJORDINATION 87 



The Nervous System 87 



The Sense Organs 9 1 



The Skeletal and Muscular Systems 91 



The Endocrine System 95 



COORDINATION WITH SPECIAL REFERENCE TO THE EXTERNAL 

 ENVIRONMENT 95 



Basic Mechanisms of Nervous Coordination 95 



Localization of Function in the Nervous System 101 



Reception and Conduction 105 



Dischart^c and Response 1 1 3 

 COORDINATION WITH SPECIAL REEERENCE TO THE INTERNAL 

 ENVIRONMENT 1 1 5 



Regulation by Autonomic Nerves 1 15 



Regulation by Endocrines 1 17 



Regulation of Breathing and Body Temperature 124 

 SUMMARY 126 



5 REPRODUCTION AND DEVELOPMENT IN CHORDATES 128 



THE REPRODLTCTIVE SYSTEM 128 

 DIFFERENTIATION OF THE GERM CELLS 133 

 REPRODUCTION 139 



Historical 139 



Methods of Reproduction 141 



Fertilization 142 

 DEVELOPMENT 145 



Cell Division 146 



Cell Localization 151 



Cell DifTerentiation 158 

 METABOLIC REQUIREMENTS OF EMBRYOS 159 

 EXPERIMENTAL MODIFICATION OF DEVELOPMENT 165 

 SUMMARY 169 



6 HEREDITY AND VARIATION 172 



THE METHOD OF BIOMETRY 173 



THE mf:thod of experimental breedinc; 175 



Mendel's Contribution 175 



Extension of Mendelian Theory 177 

 the method of CYTOLOGY 185 



Chromosomes as Carriers of the Genes 185 



Linkage 1 90 

 the method OF experimental embryology 194 

 human inheritance 197 

 heritable variations 201 



