FERTILIZATION 



29' 



mitosis, a reduction, qualitative as well as Dumerical, in all respe< 

 similar to that accomplished in the regular heterotypic mitosis, would 

 be brought about if the pairing members are qualitatively different. 

 But instead of such a separation, each member of each pail 

 transversely, giving 4x segments which are equally distributed to the two 

 daughter nuclei, each of the latter receiving the diploid number. Since 

 the 4x segments become more or less intermingled before their distri- 

 bution it is probably impossible to determine jusl which ones pass to 

 each pole. If both halves of one transversely divided chromosome p 

 to one pole (see Fig. 122), that daughter nucleus only, and not the oth< 

 will receive the kind of chromatin carried by thai chromosome, so that 



CLf.AVA&£ MITOSIS LQUATlONAL 



A- 



J& 

 CD & 



FUSION NUCltUi 



V 



St&fJLNTATlON 



V W 



CLCAVA&C. MlTOJli DlffCRCNTlAl 



Fig. 122. — Diagram showing the behavior of the chromosomes in fertilisation and tin- 

 first embryonal mitosis as usually interpreted (upper part) and according to Hut. Inn- 

 interpretation (lower part). 



the two nuclei will be qualitatively different. A qualitative reduction 

 will have occurred, but without a change in the Dumber of chromoson* 

 since each old chromosome has become two new oni It. on the other 

 hand, the two halves of the transversely segmented chromosome regularly 

 pass to opposite poles, each daughter oucleua will receive a hah' of each 

 and every parental chromosome: thus if there are just as many kinds of 

 chromatin as there are chromosomes, these nuclei will I..- qualitatively 

 alike, just as they would be had the division hern longitudinal instead of 

 transverse. But, as has been stated in the chapter on reduction and will 

 be developed at greater Length in Chapter XVII, there is a considerable 

 body of evidence which indicates that each chromosome is Dot only 

 qualitatively different from its fellows, but possesses a linear differen- 



