Aug. loifl.] THE CORIU'I.ATIOIS IM THE DIEIEREMUATliW. 



-167 



1 Sexually not diifercntiated, " vegatative." 



2 Unisexual, " male," bearing only antheridia. 



3 ,, " female," bearing only archegonia. 



4 Bisexual, " iiermaphrodite," bearing both antheridia and 

 archegonia. 



The intcusitv of diflFerentiation in a single prothallium can be 

 expressed b}^ the number of antheridia and archegonia produced. A 

 single prothalium can be considered as a -population composed of a 

 group of sexually not differentiated gamctofjhytie cells, each of which 

 is capable of producing a new individual jirolhallium by adventitious 

 growth. Hence the number of antheridia and archegonia produced on 

 a prothallium can be regarded as an expression of the intensity of sex 

 differentiation. But when we consider a population of prothallia, the 

 expression can not be made bj^ a simple manner. A total number 

 of sexual organs and the number of individuals differentiated in diverse 

 ways must Ije con.sidered. Even if the total number of sexal organs 

 produced in two populations be the same, the manner of their distribu- 

 tion may be quite different. A population may be composed of the 

 following : 



Here An is tiic number of individuals which hear autlieridla only. 

 Ar is the nuinher of individuals whieh bear archegonia only. 

 Arn is the number of individuals which bear both anthoridis and archegonia. 

 U is the number of individuals which sexually not difterentiated. 



