GENESIS. 



215 



Tifieidw, parthenogenesis appears to be a normal process — 

 indeed, so far as is known, the only process ; for of some 

 species the males have never been found. 



A general conception of the relations among the different 

 modes of Genesis, thus briefly described, will be best given 

 by the following tabular statement. 



Genesis is 



Homogenesis, which is Gamogenesis 



or 



Oviparous 



or 

 Ovo-viviparous 



or 

 .Viviparous 



f Gamogenesis 



. HeterogenesiSj which is \ ° ( Parthenogenesis 



with 



[ Agamogenesis 



Pseudo-parthenogenesis 

 or _ f Internal 

 L Metagenesis^ or 



I External 



This, like all other classifications of such phenomena, pre- 

 sents anomalies. It may be justly objected, that the processes 

 here grouped under the head agamogenesis, are the same as 

 those before grouped under the head of discontinuous develop- 

 ment (§ 50) : thus making development and genesis partially 

 coincident. Doubtless it seems awkward that what are from 

 one point of view considered as structural changes, are from 

 another point of view considered as modes of multiplication.* 



* Prof. Huxley avoids this difficulty by making every kind of Genesis a mode 

 of development. His classification, which suggested the one given above, is as 

 follows : — 



("Continuous 



Growth 



Development 



( Metamorphosis 



I Metagenesis 

 Parthenoge 

 Gamogenesis 



