40 H. M. WOODCOCK. 



There can be little doubt that the above series represents 

 what has been gone through in the nuclei shown in fig. 4G. 

 These are two nuclei of the eight -nuclear stage to which 

 reference has already been made; that is to say, they are 

 nuclei of the second generation only of daughter-nuclei. 

 They are very similar in constitution to those of fig. 47. The 

 chromatin grains on the reticulum are not all of equal size; 

 some are larger than others, and many of these are probably 

 directly derived from the fragments of the karyosome. The 

 process in this case, therefore, has evidently been more rapid 

 and has taken place earlier, the fragmentation of the daughter 

 karyosomes perhaps commencing before the parent-nucleus has 

 divided. Hence there is a certain variability in the time 

 elapsing between the first break-up of the karyosome and its 

 final incorporation with the rest of the nuclear material as a 

 part of the chromatic reticulum.^ 



(7) Nuclear Multiplication. 



(a) Nature of the early nuclear divisons. 



With regard to the manner in which the first nuclear 

 divisions take place, I have not the least doubt that they are 

 purely direct or amitotic. Unfortunately, I have no prepara- 

 tions showing the earliest ones, but in a section through a 

 sporont containing about thirty daughter-nuclei of the fourth 

 generation there is still one of the nuclei of the third genera- 

 tion dividing directly into the two of the fourth, in a manner 

 that is perfectly unmistakable. It is shown in fig. 47 c, and 

 as to its absolutely amitotic character there can be no 

 question ; the nucleus has become constricted in the middle 

 and the two halves are now being cut off from each other, 

 half the chromatic grains going to one portion and half to 

 the other. There is not the slightest sign of any attraction- 



1 A similar fragmentation of tlie karyosome witli subsequent dissolution iu 

 tlie nucleoplasm, followed by increased cliromaticity of the latter, is also 

 described by Berndt (loc. cit.) for Gregarina cuneata, and by Caullery 

 and Mesnil (5) for Selenidium sp. 



