146 



of cleavage, leading up to the formation of microraeres has not 

 been followed, but from apriori considerations, I should expect such 

 stages to have eight instead of ten cells. Each then would resemble 

 a half egg having four macromeres in the one zone (as these cer- 

 tainly had), two cells in the middle zone (as these may possibly have had) 

 and two micromeres (of which there can be no doubt). Until this 

 point is definitely settled it is well not to attempt an explanation of 

 the phenomena. Of one fact there is however, no doubt, that the 

 micromeres form in these fragments at an earlier stage than in the 

 normal egg. Also it is clear that the number of the micromeres is 

 then less than the normal. 



In another egg-fragment of seven cells there were four macro- 

 meres in the one zone, two macromeres in the middle zone and one 

 micromere in the other zone, — it is probable that here the second 

 micromere had not yet formed. In another egg-fragment there were 

 four macromeres below, four in the middle and one micromere above. 



Pig. 3. 



The karyokinetic phenomena in the shaken eggs are often remark- 

 able; the compound divisions of the chromatin produce most complex 

 figures, riasters, tetrasters etc. were very common. That this is due 

 in most cases to polyspermy, as Hertwig believed, there can be no 

 question, as stained preparations of these eggs show them to be, pre- 

 vious to division, Polyspermie. In one case I saw two spermatozoa 

 both conjugating with the female pronucleus i. e. each was flattened 

 against the nuclear membrane. 



I attempted to find out whether the compound karyokiDetic figures 

 are entirely the result of polyspermy, or due in part to the maltreat- 

 ment of the eggs. Eggs in the two cell stage were violently shaken, 

 but none of the compound karyokinetic figures were found at the next 

 division. I cannot but think nevertheless that at times the pheno- 

 menon may be due to the fragmentation of the nucleus due to its 

 pathological conditions. 



Many of the shaken eggs burst the outer membrane and then a 

 partial protrusion of the protoplasm took place. The first nuclear 



