34 THE EVOLUTION OF THE META20A 



field of biology) which wishes to see a recapitulation of 

 the phyletic stages (i.e. the characteristics of the grown-up 

 forms) in the ontogenies of their descendants, i.e. of the recent 

 animal species. Garstang, was the first scholar to make it 

 clear that the ontogenetic morphogeneses which are cons- 

 tantly repeated in each succeeding generation are also cons- 

 tantly changing. 



The changes in the ontogenetic process, whether the 

 introduction of new characteristics or the loss of charac- 

 teristics and peculiarities which had previously existed, cannot 

 possibly be considered to originate in an adult stage. It is only 

 if we accept the standpoint of Lamarckism, that we could 

 take a possible recapitulation of characteristics of the grown 

 up individual into consideration. 



In this way, and to the great regret of the comparative 

 morphologists, the recapitulations which can take place during 

 the ontogenies will be found to be limited, even if not 

 completely eliminated. It is not true when it is said— as 

 this can be frequently heard— "that Haeckel's law is not 

 generally valid but that instead its validity is only Hmited ;" 

 in reality this supposed law is basically wrong. Nevertheless, 

 there are recapitulations in ontogenies and these recapitu- 

 lations are such that they can be of good use and service to 

 a phylogenist. It is necessary to proceed very cautiously when 

 in search of these recapitulations. One must be constantly 

 aware of the fact that these are really ontogenetic characteris- 

 tics that are recapitulated. This, however, does not exclude 

 the possibility that these same characteristics eventually 

 appeared in the grown up stages of their ancestors. 

 These characteristics remain, even if they can be observed 

 only under special circumstances of morphogeny, in spite of 

 the fact that they had long been lost in their grown-up stages 

 because of suppression due to the natural selection. In this 

 way the phylogenist is fully justified in using those characte- 

 ristics that have developed during ontogeny for his conclus- 

 ions regarding the interrelationships between such animal 



