GERM CELLS OF COELENTERATES 405 
alone, since the nucleolar substance remaining continues its disso- 
lution and discharge into the cytoplasm. However, there is in 
no case any indication of the formation of a spireme previous to the 
formation of the chromosomes. Nor is there such aspireme 
in the eggs of Tubularia crocea or Pennaria tiarella, the chromo- 
somes coming from the delicate reticulum of the nucleus. 
Sections of eggs of Gonothyraea lovenii from Naples, show 
the same general relation of the reticulum, the nucleolus, and the 
nucleolar fragments, and .the same position and behavior of the 
chromosomes as already described for Campanularia flexuosa. 
Whether this applies to all the details of the behavior of the eggs 
and their ingredients has not been determined, but there is a 
very close similarity in general. 
4. Polar body formation 
In whatever manner the chromatin of the nuclear reticulum 
condenses, there comes a time when the nucleus is withoutany 
trace of a nucleolus and the chromatin within is grouped into 
grains arranged in a very close reticulum—a stage between figures 
17 and18. When this condition is reached the nuclear membrane 
breaks, the chromosomes form and enter the spindle, and the 
divisions into the polar bodies and the egg occurs. Figure 18 
shows the formation of the polar spindle outside the nucleus, the 
nuclear membrane broken and the chromatin granules escaping 
into the cytoplasm. In this figure, and in the egg from which the 
figure was made, the chromosomes were not yet formed. Whether 
it is usual for the chromosomes to delay their actual formation till 
after the rupture of the germinal vesicle I do not know, but 
such was the case in this particular egg. A point of significance 
should be noted in figure 18, namely that some of the chromatin 
granules, are escaping from the germinal vesicle through the 
broken wall and may be seen in the cytoplasm, while others are 
evidently attracted toward and are arranging themselves along 
the fibers of the developing spindle. This means that, of the chro- 
matin which has as its function the division of the egg, there is 
only a portion needed for the new cells, the rest is superfluous and 
passes into the cytoplasm. In spite, therefore, of the large amount 
