WHAT IS PARTHENOGENESIS ? 339 



admit that there is nothing more marvellous in an ani- 

 malcule reproducing several millions of animalcules by 

 spontaneous fission, than in a plant being constructed 

 out of several millions of cells, each produced by a 

 spontaneous fission ; in each case the marvel is the 

 same — the process the same. It is not more marvellous 

 that an Aphis should produce another Aphis full-formed 

 from its own substance, than that a lobster should out 

 of its own substance replace a broken claw. 



The peculiarity of Parthenogenesis which has most 

 attracted and puzzled naturalists is the fact that each 

 generation is unlike its parent. In Steenstrup's words : 

 " Generation A produces generation B, which is dissi- 

 milar to itself; whilst generation B produces genera- 

 tion C, which is dissimilar to itself, but which returns 

 to the form of generation A." This, on closer scrutiny, 

 becomes very dubious. Agassiz has pointed out the 

 identity in structure of the Medusa and Polype ; and 

 although there are formal difierences between these two 

 animals, in higher animals such differences grow less, 

 and finally disappear. The Aphis produces a larval 

 Aphis, which only difiers from its parent in the imper- 

 fection of certain organs, and these imperfections are 

 not constant ; the larva has sometimes wings. The 

 virgin product of the silkworm Moth is every way in- 

 distinguishable from the products of fertilised eggs. 



What, then, is the theory of Parthenogenesis to which 

 this discussion conducts us ? Simply this : The phe- 

 nomenon is not a deviation from the ordinary laws of 

 Eeproduction, but a derivation from those laws. What 



