CONTENTS 



Preface vil 



Introduction x 



Chapter 1. Cnidaria as the Only Coelenterata 1 



The systematic position of the Spongiae 1 



The systematic position of the Ctenophor a 8 



Cnidaria as the only Coelenterata 23 



Something about the methods that can be used in connection with 



the construction of the natural animal system 28 



The significance of the sessile way of life 47 



The role of the polymerization and of subsequent oligomerization 



during the phylogeny 52 



The validity of Watson's rule for the Invertebrates 68 



Chapter 2. The Previous Interpretations of Cnidaria 73 



The origin of Cnidaria 87 



The right sequence of the Cnidaria groups 95 



Why is there no msdusa form in Anthozoa? 103 



The primarily solitary polyps appear in Anthozoa only 106 



Polymorphism has reached its climax in Hydrozoa 109 



The regressive development of the intermediate layer in Cnidaria 112 

 The morphologic proofs of the new interpretation of the phylogeny 



of Cnidaria 114 



Muscular tisue 114 



The nervous system 124 



The emunctory-excretory organ 137 



The genital system 145 



The alternation of generations in Cnidaria 153 



The digestive system 163 



The skin and cnidae 190 



Ontogeny (The development of the embryo) 204 



Asexual reproduction and the regeneration 213 



The endosymbiotic mononuclear algae 222 



Chapter 3. The Consequences of the New Interpretation of 



Cnidaria 226 



The new system of the Cnidaria 229 



The rank and the position of Cnidaria in the animal system . . 243 

 Discussion of the new interpretation of the evolution of Cnidaria 245 



The probable origin of Cnidaria 248 



The larvae of Cnidaria 259 



A comparison of Cnidaria larvae with other larvae 266 



The origin of the Turbellaria 269 



The origin of the acoelous Turbellaria 273 



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