Aug. ll'l!).] 



THE CORRELATION IN THE DIFFERENTIATION. 



163 



bearing jirotliallia were united into a single individual. In the course 

 of development, some of the prothallia in the culture were changed 

 from ameristic to nieristic or vice versa, i. e. the growing point was 

 established or disorganised. These changes responded to sex differentia- 

 tion, but the manner was always such that the differentiation of one 

 sex su4)pressed the other. One of the prothallia showed for example, 

 that it had been ameristic and no sex differentiation occured, but that 

 since the growing point was established, the heart-shaped prothallium 

 w^as formed and five arclicgonia were produced. The growth became 

 again irregxdnr. The differentiation of sex at that part was such that 

 the antheridia formation was only possible. There were counted thirty 

 five antheridia. Another prothallium showed that there was an inter- 

 val between the formation of archegonia at the separate portion. 

 When such periodicity in growth and differentiation took place, the 

 result wiis to foi-m a twin-like prothallium, as if two heart-shaped ones 

 were conjugated. Some of the well grown individuals in the popu- 

 lation from which the above stated examples were taken are as 

 follows. 



Table VI. Blechnum nipponicum. 



