I. 1 



I. 4b 



A Porifera 



B Coelcntcrata 



C Vermes and Onychophora, Tardigrada and Linguatulida 



D Arthropoda 



E Mollusca 



F Bryoroa, Entoprocta. Brachiopoda and Hemichordata 



G Echinoderniata 



H Urochordata and Cephalochordata 



7 Further development of Vertebrates 



(including complete and partial — e.g. early — development) 

 a General investigations 



1 General subjects 



2 Complete develcpmcr.t 



3 Partial development 



4 Implantation and placentation 



b Early development, gastrulation, etc. 



1 Early development 



2 Gastrulation and formation of germ layers 



3 Development of foetal membranes 

 c Neurulation. etc. 



1 Neurulation (s.s.) 



2 Development of neural crest 



3 First larval development 



d Development of part of the organism 



1 Head 



2 Extremities 



3 Tail 



e Development of special organ-systems 



(Cf. general subdivision p. 153 — 155) 

 f Histo- and cytogenesis 



8 Growth and differentiation (Invertebrates and Vertebrates) 

 a Growth 



a/b Growth and differentiation 

 b Differentiation 



156 



