158 Trow . — Observations on the Biology and 
following upon the spirem-stage ; but detailed study finally 
led to a positive and definite rejection of this view. As the 
matter may give rise to future discussion, it may be useful 
to give categorically my reasons for this. They are as 
follows: — (1 ) The very various and frequently fantastic arrange- 
ment of the presumed chromosomes ; \d) the unstained 
matrix in which they lie ; (3) the absence of a nuclear mem- 
brane ; (4) the variation in the number of granules in the 
different groups ; (5) the demonstration of the prophases 
of a typical indirect division at a much earlier stage in the 
development of the oogonium ; (6) the presence of typical 
nuclei side by side with them in the same section and differing 
from them in structure ; (7) the impossibility of tracing the 
earlier stages in their development ; and (8) their very 
sudden disappearance as if dissolved by the protoplasm. 
The interval of time required for the passage from the stage 
represented in Fig. 42 to that in Fig. 41 cannot be much 
more than one hour. It may be concluded then, that in 
all probability, the supernumerary nuclei, multiplied to some 
extent at any rate, if not doubled, by indirect divisions, 
undergo digestion by the protoplasm. 
The eggs now commence to form, and in the stages of 
balling it is easy to demonstrate in the centre of each mass 
of protoplasm a single nucleus. This nucleus is poor in 
chromatin and is still unprovided with a nucleolus, but has 
a distinct nuclear membrane and is surrounded by a dense 
mass of fine-grained protoplasm. It is at this stage, repro- 
duced in Fig. 43, that the fibrous structure of this enveloping 
mass is alone to be clearly seen. The oil-globules are repre- 
sented by the cavities in which they lay, and occasionally, 
in the case of those lying either partly or wholly in the 
vacuole, by the skeletons we have already described. Finally 
the eggs are produced. 
All unfertilized eggs that have been examined in sections 
are of somewhat irregular shape, as, for example, those in 
Fig. 44. In the centre of each there is always a nucleus, 
perfectly well defined to one who has traced it through the 
various stages of karyokinesis. 
