NEW INTERPRETATION OF CNIDARIA 317 



the three body layers (which are called by Steinbock ecto- 

 plasmodium, mesoplasmodium, and entoplasmodium) are all 

 capable, that they are able to develop a new unit even if 

 cut into the smallest dimensions (a minute-piece measuring 

 157 a punched from the posterior end of the animal). They 

 have therefore the character of a primary plasmodium. 

 Where can we find a similar case in the whole animal world 

 of the Eumetazoa that an entoderm can regenerate into a 

 whole new anim.al even if it exists in a syncytial state? 



The most important element among Reisinger's arguments 

 against the existence of a truly primary plasmodium in the 

 Eumetazoa (our thesis of a polykaryonic and plasmodial origin 

 of the Eumetazoa loses every foundation if there are no such 

 Plasmodia) is, according to Reisinger, "Die ausnahmslose zellige 

 Primarstruktur friiher Embryonalstadien" (Reisinger, 1958: 

 642); or, in other words: the ontogenies of the Turbellaria. 

 Among these, the Acoela begin with a cleavage, thus 

 with a formation of cells which is only subsequently followed 

 by a formation of syncytia. Steinbock has already given an 

 answer to this observation. Above all, very Little is known 

 about the early ontogenies of the most primitive Acoela. We 

 agree with Steinbock who does not think that species of 

 Metazoa will be found with the oldest form of the early 

 ontogeny (i.e. a plasmodial state) preserved. Evolution has 

 led in the inactive sessile polycellular algae (Caulerpa) to 

 a state where a division of karyons takes place as an obvi- 

 ously secondary phenomenon instead of a cleavage or of a divi- 

 sion of the zygote. 



Scholars have become used, under the influence of the colo- 

 nial theory and of the blastula-gastrula, to see in the early devel- 

 opment of the Eumetazoa by w^ay of cleavage (the division 

 of karyons that can be observed in insects was naturally im- 

 mediately explained as a secondary caenogenesis) a recapitula- 

 tion of the phylogeny which is supposed to repeat the primi- 

 tive formation of colonies by the monocellular Flagellata. 

 Scholars have begun only recently to analyse experimentaly, 



