NEW INTERPRETATION OF CNIDARIA 279 



termediate forms," "certain special homologies." Steinbock 

 (1958 : 204) is right when he emphasizes that Remane is much 

 less strict when he tries to prove his own thesis and that in 

 connection with his thesis he is satisfied mainly wdth one rather 

 remote analogy of green algae (the frequently misused 

 Volvox) as well as with an (according to our interpretation 

 wrong) application of the misused "fundamental biogenetic 

 law" as it was proposed by Haeckel (cleavage = a recapitulat- 

 ion of the formation of the colony of Flagellata, etc.). 



Several scholars have objected in principle against any 

 possibiUty of deriving the Eumetazoa from some ancestors 

 that resembled the present day Infusoria, stating that the In- 

 fusoria are a much too speciaHzed animal group, a blind alley, 

 and that therefore no new animal type could possibly have 

 evolved from them. The fact that they harbour of two nuclei 

 only with a clear dimorphism of the two nuclei, the absence of 

 free gametes, conjugation as an isolated form of the sexual re- 

 production are all unique properties which can only be a 

 result of a long evolution in their own direction. I must admit 

 the great importance of these differences and that at the first 

 sight these differences really seem to disprove a possible deduct- 

 ion of Eumetazoa from Infusoria. I myself (Hadzi, 1944 : 160) 

 was initially under the influence of these facts: I endeavoured 

 to avoid them and tried to find an origin of the Acoela farther 

 back among the Protozoa, i.e. among the polykaryonic Flag- 

 ell?.ta. This, however, is in principle not so important. 



After a thorough analysis of the sexual conditions that can 

 be found both in the Infusoria and in the Acoela and after an 

 intensive comparison of the two (Hadzi, 1950) I have finally 

 come to the conclusion that it is possible to overcome these 

 seemingly unbridgeable difficulties, that these differences do 

 not represent a matter of principle, that instead they have only 

 been gradually increased. This has finally led to the widely 

 different forms that can be observed in the extreme cases in the 

 two animal types. In this connection I can also mention the 

 study by Hansen (1958). 

 19* 



