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William S. Marshall and Paul H. Dernehl. 



there also being a Variation in its thickness over different parts ol 

 the same egg. It is true that in general the ventral surface has a 

 thicker layer than the dorsal, but this is not always so, it being 

 often more marked at other parts. 



Having now arrived at a stage in the development of the egg 

 just preceeding the arrival of the eleavage nuclei at the egg's surface 

 and their entrance into the Keimhautblastem, we will proceed to a 

 study of the nuclei we have seen are present wilhin the egg. In 

 any stage during the pre-blastodermic development of Polistes we 

 find, as already stated, that the difference between the many nuclei 

 within the egg is one of position. The similarity between the eleavage 

 and the yolk nuclei was, we believe, first pointed out by Cholod- 

 kowsky (13) and Wheeler (60), and has later been referred to by 

 Dickel (14). Much support was formerly given to the view that the 

 yolk nuclei divide amitotically and are thus distinguished from the 

 mitotically dividing eleavage nuclei. Cholodkowsky (13), Heider (23), 

 Wheeler (60), Tschuproff (55) and Schwartze (51). We cannot 

 agree with those who take this view; the Statement we made that 

 all nuclei, previous to blastoderm formation, are, in the egg of Polistes 

 similar, except in position, includes also the more minute strueture 

 of either resting or dividing nuclei. We find that not only do all 

 nuclei divide similarly but that the resting nuclei are alike at from 

 whatever point within the egg they are selected. 



We find in Polistes that all eggs, previous to blastoderm forma- 

 tion, show in their dividing nuclei an abundance of those in the 

 equatorial plate stage, this stage not only being more abundant than 

 any other, but it is found oftener than all other stages of mitosis 

 combined. Considerable differences were shown between the various 

 eggs examined; some with many nuclei would have them all in a 

 resting stage, others would have part resting, and part in various 

 stages of mitosis. Eggs containing many dividing nuclei would 

 generally show them in different stages of division, exceptions to 

 this being found however in some eggs in which all dividing nuclei 

 were in the equatorial plate stage; this is the only stage of mitosis 

 ever found exclusively within an egg. It was also noted that late 

 anaphase stages were very prevalent. Heider (23) noticed that in 

 an egg of Hydrophüus most of the many nuclei would be in the 

 same stage of mitosis. The same thing was noticed by Wheeler (60) 

 in Boryphora. He also called attention to the great preponderance 

 of resting nuclei. A somewhat different condition was noticed by 



