GENESIS. 



215 



Tineidw, 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 

 bv the following tabular statement. 



Homogenesis, whict is Gamogenesis - 



Genesis is « 



or 



. Hetcrogenesis, which is 



[" Gamogenesis 

 alternating 

 with 



[ Agamogenesis 



' Oviparous 



or 

 Ovo-viviparouQ 



or 

 Viviparous 



' Parth enogenesis 



or 

 Pseudo -parthenogenesis 



or ^ r Internal 

 Metagenesis \ or 



[ External 



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

 sents anomalies. It may be jnstly 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 change-s, 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 af 

 follows : — • 



Continuous 



Growth 



Development- 



( 



( Metamorphosis 



/ Metagenesis 

 I Agamogenesis | 

 .Discontinuous | ( Parthenogencccn 



' Gamogenesis 



