ALIMENTAEY TRACT OF CULEX PIPIENS 611 



cells are on the point of disintegration and cell boundaries can 

 not be definitely determined. On the other hand, a cell con- 

 taining a complex of three or four times the normal number of 

 chromosomes may be of about the same size as one with six 

 chromosomes (figs. 27 to 30). It would seem therefore, as if 

 the growth of chromatin might be greatly accelerated in the 

 'resting stage/ followed by rapid sphtting in the prophases, so 

 that the chromosomes retain their normal size, while the cyto- 

 plasm grows, with or without division, at the normal rate. 

 However that may be, it is e\ddent that there is a great increase 

 in the amount of chromatin in the old cells of the alimentary 

 tract, preparatory to their absorption by the new. 



MITOSIS IN MULTIPLE-COMPLEX CELLS 



In the late anaphase of cells in which the number of chromo- 

 somes is not large, the chromosomes appear to lie in groups of 

 three. Where the number is great, it is not possible to make 

 out the exact arrangement, but from conditions in the early 

 prophases, it is believed that the chromosomes pass into the 

 resting stage in three groups, each group made up of the indi- 

 viduals derived from one of the three pairs of chromosomes of 

 the original complex. Now and then a pair of chi'omosomes 

 lags behind on the equatorial plate. An interesting case of this 

 appears on Dr. Stevens' slide, on which such a pair occurs in 

 several cells of the intestinal epithelium of the same individual 

 (figs. 5 and 31). In telophase, the nuclear wall can not be dis- 

 tinguished, but the region of the nucleus is suggested by a light 

 space about the telophase masses. 



As the chromosomes pass into the 'resting stage' they grad- 

 ually lose their staining power and become indistinguishable 

 within an irregular mass taking a pale blue-gray stain with 

 haemotoxylin (figs. 3, 4, and 5). For a time, scattered bits of 

 chromatin remain visible within this mass, but these eventually 

 disappear, and only a pale nucleolus can be seen. The chro- 

 matin next makes its appearance in granules about the periph- 

 ery of the nucleus and in faintly staining threads centering 



