No. 504] NOTES AND LITERATURE 



823 



for the influence of the spermatozoa in sex-determination and 

 for selective fertilization. 



While the facts regarding the honey-bee and Dinophilus offer 

 serious obstacles for the general application of Correns's prin- 

 ciples of sex-determination to plants and animals, he finds on the 

 contrary much similarity between his results and the cytological 

 findings of E. B. Wilson for many of the Hemiptera. Taking 

 Protenor and assuming that the spermatozoon with the seven 

 chromosomes (including the accessory) carries the recessive 

 female tendency, and that the spermatozoon with six chromo- 

 somes carries the dominant male tendency, then the correspond- 

 ence between the results is complete. The assumptions made 

 at first sight seem inconsistent, but they appear more reasonable 

 in the light of Correns's observations on Satureia hortensis where 

 the female tendency — which becomes patent by reason of the 

 latency of the anlage of the male tendency (in originally her- 

 maphrodite forms) — dominates over the hermaphrodite tendency 

 in crosses, when ordinarily the anlagen for hermaphroditism are 

 active besides the passive anlagen for the female tendency (in 

 gynomcecious forms). 



Correns finds it difficult to believe that the idiochromosomes 

 are the material vehicles of the sex-tendency, since the disappear- 

 ance of the mate of the accessory chromosome in Protenor seems 

 to show directly that it was no sex-determinant. Both germ- 

 cells contribute both anlagen; the idiochromosomes can, there- 

 fore, simply aid the development of one sex-anlage or hinder the 

 other. If we accept the idea that they are also the carriers of 

 the sex-anlagen then the spermatozoon of Protenor with six 

 chromosomes would have no sex-anlage ; and ephebogenetieally de- 

 veloped it would give rise to an organism without sex. If the 

 anlagen are present outside of the idiochromosomes then the 

 spermatozoon thus developed would give origin to a hermaph- 

 rodite form. There probably are not two kinds of eggs. The 

 contrary assumption rests upon another; ?'. e., selective fertiliza- 

 tion. There is no experimental evidence of selective fertiliza- 

 tion in the case of Hemiptera. If one accepts Wilson's sug- 

 gestion that in cases like Nezara (where the idiochromosomes are 

 alike) half of the spermatozoa have an active idiochromosome 

 (aiding the development of the female sex) and half a passive 

 one (permitting the male sex to develop), and that the latter 

 in consequence of its passivity become reduced (as in 



