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William S. Marshall and Paul H. Dernehl. 



We do not hold tliat these multinucleate masses are formed by divi- 

 sion of the nuclei alone, but that more active in their formation 

 appears to be a joining of uninucleated masses we have earlier 

 described. The number of the multinucleate masses is much less 

 than were the Single nuclei present just before blastoderm. formation. 

 We find, also, that the outline of each multinucleate mass is much 

 more regulär and clearly defined than in the yolk nuclei. Finally 

 we find that the nuclei of the two groups, cleavage and yolk nuclei, 

 have each an entirely dirferent fate. The first, after forming the 

 blastoderm cells, continue to divide mitotically and take part actively 

 in the development of the insect. The yolk nuclei apparently reach 

 a stage in which active division ceases, but before this takes place 

 true mitotic division is lost or greatly changed. As already men- 

 tioned, true mitosis does not cease all at once and amitosis take its 

 place, but both kinds of division may be present in the same egg. 

 Amitosis was found but rarely, no egg being observed which contained 

 many yolk nuclei so dividing. In the last stages of development 

 which were here described, we found, fairly abundantly, nuclei which 

 showed a completed division quite different from what we earlier 

 described. Whether these were the result of a direct or an indirect 

 division we cannot say; the presence of more darkly stained Strands 

 between the nuclei might point to a mitotic division, but the fact 

 that these figures were never found in pre-blastodermic stages would 

 point, we think, to their being the result of amitotic division. Another 

 view, which we hold as most likely, is that the method of mitosis 

 has changed and these figures (Figs. 56, 57, 58, 59 and 60) are the 

 result of a very greatly changed mitosis resulting in the Separation 

 of the daughter nuclei, but in a method which, probably, dirfers 

 soniewhat from what we have hitherto recorded. 



The nuclei which were amitotic in their division at first elongate 

 (Figs. 50 and 51), their outline later resembling that of a figure 8 

 (Fig. 52). The chromatin granules are larger than in those nuclei 

 seen in earlier stages, but become finally arranged so that the 

 resultant nuclei will each contain approximately one-half of the 

 chromatin. We find here, what has often before been noted, the 

 fact that these nuclei are somewhat larger than normal. 



The Statement of Schwartze (51) that the yolk nuclei, when 

 they become such, degenerate, would appear to us to be, in part at 

 least, incorrect. In the early stages of cleavage, after the two groups 

 of nuclei have become separated from each other, the inner group 



