PALINGENESIS AND KENOGENESIS. 409 



The fact is simply shown by a comparison of the various 

 histories of individual evolution of higher and lower animals 

 of the same tribe.-^^^ 



In order to give its due weight to this significant 

 relation, we have classed the whole series of ontogenetic 

 phenomena, of the phenomena occuring in the evolution of 

 an individual, in two different groups, placing the palin- 

 genetic phenomena in one group, the kenogenetic in the 

 other. To Palingenesis, or inherited evolution, we referred 

 those incidents in germ-history which may be regarded as 

 accurately inherited from the history of the tribe. On the 

 other hand, we applied the term Kenogenesis, or vitiated 

 evolution, to such ontogenetic processes as were not 

 directly referable to corresponding phylogenetic incidents, 

 but were, on the contrary, to be explained as modifications, 

 or vitiations, of the latter. In consequence of this critical 

 separation of palingenetic from kenogenetic germinal 

 phenomena, the fundamental law of Biogeny was more 

 accurately defined as follows : The short and quick history 

 of the germ (Ontogeny) is a compressed epitome of the 

 long and slow history of the tribe ; this epitome is the 

 more correct and complete, in proportion as the inherited or 

 epitomized evolution (Palingenesis) is retained by heredity, 

 and the less vitiated evolution (Kenogenesis) is introduced 

 by adaptation. ^^ 



In order correctly to distinguish the palingenetic from 

 the kenogenetic phenomena of germ-history, and from these 

 rightly to infer the tribal history, we must especially apply 

 ourselves to a comparative study of Ontogeny. It is only 

 by comparing the germ-history of allied forms that we are 

 able to discover the traces of their tribal history. For this 



