WHAT IS PARTHENOGENESIS? 321 



eration, he will admit that there is nothing more marvellous 

 in an animalcule reproducing several millions of animalcules 

 by spontaneous fission, than in a plant being constructed 

 out of several millions of cells, each produced by a spon- 

 taneous 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 fall-formed from its own sub- 

 stance, than that a lobster should out of its o^vii substance 

 replace a broken claw. 



The peculiarity of Parthenogenesis which has most at- 

 tracted and puzzled naturalists is the fact that each genera- 

 tion is unlike its parent. In Steenstrup's words : " Genera- 

 tion A produces generation B, which is dissimilar to itself ; 

 whilst generation B produces generation C, which is dis- 

 similar to itself, but which returns to the form of genera- 

 tion A." This, on closer scrutiny, l)ecomes very dubious. 

 Agassiz has pointed out the identity in structure of the 

 Medusa and Polype ; and although there arc formal diffe- 

 rences between these two animals, as we ascend the scale 

 such differences grow less, and finally disappear. The Aphis 

 produces a larval Aphis, which only differs from its parent 

 in the imperfection of certain organs, and these imper- 

 fections are not constant ; the larva has sometimes 

 wings. The virgin product of the silkworm Moth is 

 every way indistinguishable from the products of fertilised 

 eggs. 



What, then, is the theory of Parthenogenesis to which this 

 discussion conducts us ? Simply this : The phenomenon is 

 not a deviation from the ordinary laws of Reproduction, but 



