METHOD OF CELL DIVISION IX MONIEZIA. 2S; 



cytologists would, I think, be willing to admit at once that 

 similar phenomena in somatic cells doubtless indicate its occur- 

 rence there. 



\\ 'r may now consider the value of such pictures as evidence 

 and tin; force of some of the criticisms made- by Richards and 

 others. 



As regards the first point, I have observed picture- of this 



kind only in region- where the nuclei are increa-in^ r in number. 



'Ie\\-ki '09 h.i- -u^e-ted that I may have mi-taken nuclear 



lu-ioii- tor divi-ion-. It would be -trance indeed it" nuclear 



lu.-ion ^hould occur only or chiefly in regions where the nuclei 



undoubtedly iticr. ;n number in some way. 



ii.it the tuo nuclei in a cell repre-eiu 



the paternal and maternal chroinatin refer- primarily to the 

 aiii]ihiltian cell- and perh. ip- he him-clf would n>t rc-ard it as 

 ad" '11111 t'<ir t! nces in .17 ' Mainly 



then- i- no evidence of t: ratii>n of the two chroinatin- in 



milotic di\i-ion in M< en in . A- iv-ard- the 



amphibian i "-1I- \\hich I ti^un-d in an earlier paper '.Child, 

 |o and l l ii -lu>uld I- <! that t ': !i.-<l 



\\ere n-.i cleava . but mo-ll\- lar\al , in \\hich I 



(i-uld IIIK! ii' ' : I took especial < iicrriiiiu'. this 



point, 'p.iratinii of paternal and maternal cliromatin in 



mitoiic di\i-ini. I d imt believe that thi- -iiu^e-tii)ii \\ill 

 "lint for the phenomena even in .1 and it certainly 



\\ ill ii">t in .I/.- 



A- i< ^ard- the po ible in ot the nuclei by migration in 



parti"iilai regions, . ,., the prinmrdia of the o'liad-. '\ichanls 

 him-elf admit- 'hat the i-\ idence tor migration U not 



strong, M' even if migration di cur in the formation 



of the -..nad-, there niu-t ne\ ei t lule be a coii-ider.tble ])riniar\- 

 increa-e in the parcnchymal mu l.-i befori' tin- ouiad- are formed. 

 Kichanl- pp. [38 9 find- the aciual increase in parenchym.il 

 nuclei to be .'.bout equal to the increase iii \olume of the pro-lot- 

 lid-. Such an increa-e i-. I belie\e, entireK' inade(|iiat"- to ac- 

 count on the b.i-i- of migration for tin- very lar^e number of 

 nuclei which appear in ^miad formation. 



t 'oncerniii;c the occurrence of mito-i- Richard-'- actual ob- 



