248 EDITH PINNET 



Figure 67 confirms this interpretation. One of the V-shaped 

 elements, which is the contribution of the foreign spermatozoon, 

 shows a new and interesting adddition in the form of a round 

 granule, a chromosome possibly, attached to one of its arms. 

 This granule evidently became united to the V-chromosomes 

 before division took place, because both of the mates resulting 

 from division show the identical arrangement. I have tried to 

 find the same combination in other cells, but although the V's 

 occur, they are not associated with any fragments of chromo- 

 somes. 



One cell was found in which division had reached a later 

 anaphase stage. Among the chromosomes lagging at the equator 

 of the spindle was one with subterminal fiber attachment. The 

 two daughter halves had almost separated. The portions which 

 extended toward the poles were drawn out into a thin thread, 

 while the free end was condensed, having the appearance of a 

 small granule. The thin strand of chromatin uniting these 

 proximal ends with the distal undivided portion lying in the 

 equatorial plane were almost ready to break. If such a break 

 occurred, it might result in the elimination of a portion of a chro- 

 mosome. Unfortmiately, the reading for this section was lost 

 and a drawing could not be made. Figure 71 shows one section 

 of an anaphase of the third cleavage. The chromosomes are 

 well separated and in most cases very obviously paired. In 

 the figure a light line unites the daughter halves of one chromo- 

 some. It will be seen that some bodies cannot be thus paired. 

 In one instance the apparent mate of a short rod consists of two 

 small round chromosomes, probably separated chromomeres. 

 In another the daughter halves of one chromosome still united, 

 are passing together to one pole. They have no counterpart in 

 the other half of the spindle. 



WTiat becomes of chromosomes which may not divide during 

 mitosis? The evidence on this point is not abundant. Figures 

 63, 65, 66, and 69, which are of some of the conditions found, 

 demonstrate clearly that not all of the chromatin reaches the 

 poles during the anaphase or becomes incorporated in the new 

 nucleus. Figure 63 show^s chromosomal vesicles in the region of 



