.4 •.. Art. 3.— Xaohide Yatsu : 



than ''yolk," In the material fixed witli Flemming's fluid the- 

 alveolar substance is completely dissolved, being represented bj^ 

 holes. Whatever its chemical nature may be, it is certainly not 

 similar to Avhat commonly goes luider the term yolk. In the 

 entoplasm no axial differentiation can be detected; tlie size 

 and nature of the alveoles are the same throughout the egg.' 



II. Polocytes. 



I have nothing to add about the formation of the polocytes, 

 excepting that in one case a maturation spindle with no pok'-ra3\s- 

 was met with in an ectoplasmic accumulation (Flemmixcj's fluid 

 material). 



In tlie living egg it was not difficult to see the polocytes. 

 Pseudopodia are seen on botli the polocytes. The first polocyte 

 loses them and invariably divides in two; each part has a smootli 

 surface. The pseudopodia, however, remain on the second polo- 

 cyte (PL I, Fig. 4). As to whether or no the polocytes perform^ 

 an amoeboid locomotion b}- means of the pseudopodia I have had 

 no means of determining. Yet I am rather inclined to believe that 

 they do not (cf. Chun '80 p 101). As is shown in Figs. 1, 2 and 3 

 (PL I) a thickened portion of the ectoplasm is found beneath the- 

 poloc^^tes. The egg nucleus undoul)tedl3' lies in this. The ac- 

 cumulation lasts for some time after the formation of the second 

 polocytes. But it soon disappears. 



III. Entrance of the Spermatozoon into the Egg. 



As already mentioned, when the eggs are discharged, they 

 have a thin gelatinous covering about them. When fertilized tins 

 membrane changes into a thick layer of jelly. I could not ascer- 

 tain how the process took place. It is highly j^i'obable that tlie 

 change is of the same nature as that of echinoderm eggs. In any 



1 In this connection it may be of some interest to note that Fewkes saw in the egg of 

 Jgalma a mass of rosy entoplasm at one polo ("85 p. 247). 



