Para-embryological subjects 



a General subjects 



b Reproduction 



Initial development 



a Primordial germ cells 



b Gametogenesis until completion 



1 Spermatogenesis, sperm 



2 Oogenesis, ovum 



3 Egg membranes, capsule fluids 

 c Maturation 



d Ovulation and oviposition 



e Activation and fertilization 



f Parthenogenesis 



g General subjects 



Cleavage 



a Cleavage 



b Cell-lineage 



Further development of Evertebrata 



a General investigations 



1 General subjects 



2 Complete and partial development 



3 Development of movement and behaviour 

 b Embryogenesis (and larval development) 



1 Pre-gastrulation 



2 Gastrulation 



3 Formation of germ layers 



4 Late embryonic development 



5 Larval development 



c Induction, determination etc. 



d Development of parts of the organism 



1 Head 



2 Extremities 



3 Other parts 



e Development of organ systems and organs 



(Cf. Key on p. 195) 

 Further development of Chordata 

 a General investigations 



1 General subjects 



2 Complete and partial development 



3 Implantation, placentation, extra-embryonic membranes, embryonic fluids 



4 Development of movement and behaviour 

 b Embryogenesis (and larval development) 



1 Pre-gastrulation 



2 Gastrulation 



3 Neurulation 



4 Development of neural crest 



5 Late embryonic and larval development 

 c Induction, determination etc. 



1 Induction 



2 Determination 



3 Regulation 



>22 



