NEW INTERPRETATION OF CNIDARIA 343 



ancestral forms and when it even equates these two different 

 elements. Remane would like to reach at least a compromise 

 end so he proposes that the w^ord "rule" should be used 

 instead of the word "law" while at the same time he still 

 continues to use the old word. Such a proposition, however, 

 does not touch the main problem, above all because zo- 

 ologists prefer to avoid the word "law" quite generally in the 

 modern biology, and even more so the phrase "the basic 

 law." Neither has the adjective "biogenetic" been very for- 

 tunately selected; it should be avoided because in the general 

 biology the word "biogenesis" signifies the origin of life on 

 our planet. And above all we can see how senseless it is to 

 speak in this connection of a rule if we use the expression 

 "the rule of the relation between the ontogeny and the phylo- 

 geny" (or even better: "between the ontogenies and the 

 phylogeny") instead of the phrase "the biogenetic rule." We 

 have actually here a biogenetic phenomenon which we still 

 have to study intensively, and where we are still far from 

 knowing its exact character. Would it not be sufficient if we 

 simply call this biological phenomenon a recapitulation in 

 order to characterize in this way a special case of repetition 

 which probably takes place in each ontogeny and which is 

 apparently a reiteration of characteristics and peculiarities that 

 had originally belonged to the adult stages of the ancestral 

 forms? This would then be recapitulations in a narrower 

 sense of the word which can serve as best proof in our 

 phylogenetic speculations. Yet there are also other recapitul- 

 ations (s. lat.) which may also prove useful in our phylogenetic 

 constructions which, however, must be used with consider- 

 able restraint. These are the ontogenetic repetitions of those 

 characteristics and pecuHarities which have nothing in com- 

 mon with the final stages of the ontogenies, with the fully 

 adult functioning stage. Haeckel called them caenogeneses 

 (Falschmgen, falsifications, deviations). If we look upon this 

 problem from the point of view explained here then we must 

 admit that theoretically such cases can exist where the whole 

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