264 MARY T. HARM AN. 



which is very distinctly visible in the metaphase stage is small 

 and spherical. It stains almost as intensely as the chromosomes. 

 The astral rays are short and indistinct. The chromosomes are 

 at right angles to the spindle fibers in the metaphase stage 

 (Fig. 7). A metaphase plate always shows one chromosome 

 nearer the center of the spindle than any other chromosome. 

 Sometimes it is completely surrounded by the others (Figs. 4 and 

 6) and sometimes merely one end is at the center of the spindle 

 (Figs. 3 and 5). This chromosome is always one of the larger 

 of the group of smaller ones but it is never the bent one. Few 

 anaphase and no telophaase stages have been observed. Fig. 8 

 shows an anaphase with rather indistinct spindle fibers, which 

 is characteristic of all the anaphase stages observed. The cen- 

 trosome, which shows distinctly in the metaphase stage (Fig. 7), 

 is now invisible. The chromasomes are no longer at right angles 

 to the spindle fibers but are nearly parallel with them. 



Fig. 9 illustrates the condition of the cell at the beginning of 

 the growth period. The nucleus is large and comparatively 

 clear. Some of the chromatin is in a finely reticular condition 

 and stains faintly with iron-hsematoxylin. However, a mass of 

 the chromatin retains the compact consistency and the density 

 of stain of the chromosomes (A, Fig. 9). It has a rounded form 

 like a nucleolus. The boundary between the nucleus and the 

 cytoplasm is quite evident. The nucleus continues to increase 

 in size and the reticular chromatin, which now has a greater 

 staining capacity, forms a thread or threads having a woolly 

 appearance. There is no polarization of the loops of the spireme 

 but they occupy almost all of the space of the nucleus and form 

 an irregular tangled mass. The nucleolus remains at one side 

 of the nucleus and does not have the woolly appearance that 

 the spireme has (Fig. 10). 



In the synezesis or contraction stage, the spireme seems to 

 shrink away from the nuclear wall, leaving a clear space between 

 the cytoplasm and the chromatin material. There is little 

 difference between the character of the chromatin and its 

 staining capacity in this stage and the preceding one. The 

 compact mass of chromatin never loses its identity and always 

 remains at one side of the nucleus (Fig. n). The boundary of 



