Conjugation of Polar Bodies. xxix 



second polar body, and one oozoon is left containing 

 the remaining two chromosomes. 



Assuming that the ^^^ of one of the parthenogenetic 

 species of Cynipidae had the same number of chro- 

 mosomes as the species of Ascaris just described, four 

 chromosomes would be extruded as the first polar body 

 and four would remain in the nucleus. In that of a 

 sexual species, on the contrary, six chromosomes would 

 be found in the polar bodies and only two in the nucleus ; 

 but when fertilization took place, two chromosomes 

 would enter the ovum with one spermatozoon, and six 

 chromosomes would be added to the polar bodies when 

 three other spermatozoa united with them". Thus the 

 polar bodies of one ^%% of the parthenogenetic generation 

 would contain four chromosomes available for the suppl}- 

 of germ-plasm to the next generation ; while the polar 

 bodies of a sexual egg would afford twelve chromosomes 

 for the germ-plasm of the generation that follows. It is 

 clear that if the polar bodies contain the germ-plasm of 

 the next generation they must be fertilized by three 

 spermatozoa, since in the sexual generation male and 

 female characters are equally transmitted. If this be 

 the case, we ought to find the eggs of the parthenogenetic 

 generation much more numerous than those of the 

 sexual, because the parthenogenetic germ-tracks have 

 received the produce of twelve, while the germ-tracks 

 of the sexual generation have only received that of four 

 chromosomes ; and it is to be presumed that the ova 

 produced from them would bear something like this 

 proportion to each other, if this theory held good. What 

 are the facts ? The summer sexual generations, whose 

 germ-plasm has been received from the parthenogenetic 

 polar body, produce from 200 to 400 eggs ; while the 

 winter agamous generation, which receives its germ- 



