1909] 



Y AM ANOUCHI— MITOSIS IN FUCUS 185 



sperm 



:rmy (figs 



le egg and sperm, the entry and progress of the 

 sperm in the egg cytoplasm, and the entry of the sperm into the 

 nudeus, all occur with rapidity. The chromatin of both the sperm 

 and egg nuclei forms the reticulum of the fusion nucleus. The 

 chromatin of both nuclei is mingled so as to become indistinguishable 

 {jigs, yia, b, c). The mitoses at the segmentation of 

 fertilized eggs (figs. 72a, b; 73; 74; 75a, b, c) take place as described 

 by Strasburger and by Farmer and Williams. The number 



norma 



1 64 (fig 

 sperms 



sperms 



when three sperms have entered, there are three centrosomes. In 

 case of bispermy there are developed three poles, and in case of 

 trispermy (fig. 7 6) four poles (fig. 77) are present ; for one pole has 

 already appeared before the sperm enters. In the nucleus with three 

 Poles, there are tripolar spindles, and 96 chromosomes become dis- 

 tributed upon the three spindles. The chromosomes split longitudi- 

 nally at the metaphase, and at telophase two sets of 32 chromosomes 

 m eet at each of the three poles to form three daughter nuclei. 



^ a quadripolar spindle (fig. 78) 128 chromosomes are dis- 

 tributed upon six spindles, and each of the four poles receives three 

 sets of daughter chromosomes, numbering 21, 21, and 22 (fig. 79 h )> 



form daughter nuclei. In cases of polyspermy, the formation of 



daughter 



occurs simultaneously. 



& is very interesting to note that in these cases of polyspermy 



number of the chromosomes 



Producing multipolar spindles. Whether or not polyspermy 



determined 



CYTOLOGICAL PHENOMENA 



their 



Th e problem of cilia-bearing structures and centrosomes and 



form 



| vhic h both blepharoplasts and centrosomes are present. As the prob- 

 lem * quite important, it will be treated in detail in the next paper. 



At 



chromosomes 



