404 L. DONCAHTER 



much greater than the haploid complement (twenty-eight). 

 Probahly mitotic iigm'es embedded deeply in the yolk are fixed 

 less rapidly than the maturation mitoses near the surface of the 

 egg, with the result that observations on the number and 

 behaviour of the chromosomes in the segmentation divisions 

 become untrustworthy. 



' Chromatin Elimination ' in the Maturation Divisions 



OF the Egg. 

 In my 1914 paper ^ I mentioned that ' during the first polar 

 division, a mass of granules which stain deeply with iron 

 haematoxylin is left in the equatorial plate as the chromosomes 

 travel to the poles ' (fig. 14 of that paper). No further investiga- 

 tion was made at the time on the nature or mode of origin of 

 these granules, but in a paper published almost simultaneously ^ 

 Heiler describes them in considerable detail in the eggs of the 

 moths Phragmatobia fuliginosa, Orggia antiqua, 

 L y m a n t r i a m o n a c h a , and L . d i s p a r . He gives 

 evidence that these granules are separated from the chromo- 

 somes in the early anaphase of the first polar division, and 

 maintains that in favourable cases it is possible to see that 

 each chromosome, as it divides, leaves behind on the equator 

 of the spindle a chromatin mass which for a time at least 

 preserves its identity, so that in sections of a mitosis in anaphase 

 cut at right angles to the axis of the spindle it is possible to see 

 three plates each containing the same number of chromatin 

 bodies similarly arranged — the two anaphase groups of chromo- 

 somes and between them an ' elimination plate ' consisting of 

 chromosome-like bodies having the same number and arrange- 

 ment as the chromosomes in the true chromosome plates. 

 Careful search among my preparations — both old ones and new 

 sections made for the purpose — has not revealed the existence 

 of plates with such definite, chromosome-like granules in 

 Abraxas, but in other respects my sections, when stained 



* Doncaster, L., ' Journ. of Genet.', 1914, p. 1. 



2 Seller, J., ' Archiv fiir Zellforschung.', xiii Band, 2. Heft (p. 159). 

 Leipzig und Berlin, 1914. 



