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William L. Marshall and Paul H. Dernehl, 



any nuclei in the spirem stage such as Henking (25) found and 

 figured for Pyrrhocoris. The cytoplasm is distributed evenly around 

 each nucleus which is often excentric in position, although oftener 

 central. We did not find that the nucleus occupied any regulär 

 position within its surrounding cytoplasm relative to the center or 

 periphery of the egg; the regulär movement of the nuclei towards 

 the surface of the egg and their frequent division would tend to 

 greatly disturb any regularity of position, if such were present. 

 These Statements regarding the position of the nucleus within its 

 surrounding cytoplasm hold good only until the Keimhautblastem is 

 reached after which, as we shall show later, a change takes place. 

 The general outline of the cytoplasm has often been described as 

 amoeboid, and this undoubtedly gives the best comparative descript- 

 ion. When we examine the many irregulär branching processes 

 (Fig. 11) we find that they resemble much more closely the pseudo- 

 podia of the reticulosa than the lobopods of an Amoeba. The pro- 

 cesses form a delicate branching network which it is impossible to 

 follow at any great distance. The shape of the cytoplasmic mass 

 around each nucleus is greatly influenced by the surrounding yolk 

 globules. 



A considerable Variation is noticeable in the size of the nuclei 

 from different eggs as well as of the nuclei within the same egg. 

 By measuring a number of nuclei from each of several eggs we find 

 that they are as a whole apt to be larger, or smaller, in some eggs 

 than in others. We find that in early stages of segmentation the 

 nuclei within an egg are nearly all of the same size, the differences, 

 if any, being slight. After the nuclei have wandered as far as the 

 Keimhautblastem, and even in stages a little earlier, the yolk- 

 becomes noticeably larger than the cleavage- nuclei, the difference 

 becoming more pronounced as soon as the blastoderm is formed. 

 Kulagin (33) noticed that, previous to blastoderm formation, nuclei 

 of different sizes were found within the egg, although the difference 

 in size was apparently not general. In later stages he noticed that 

 the nuclei of the blastoderm cells were decidedly smaller than the 

 yolk nuclei. Heymons (26) describes the cleavage nuclei as smaller 

 in Forficula than the yolk nuclei, and many others have called 

 attention to this and other differences in size which they noticed in 

 the eggs of the insects they studied. The difference in size which 

 we found between the yolk and the cleavage nuclei, would naturally 

 tend to disprove what we have held regarding the exact similarity 



