1898-99. | ON THE CYTOLOGY OF NON-NUCLEATED ORGANISMS, 501 
times be found in the cell. It is, therefore, not impossible to find 
frequently in cells in cultures beginning the sporulation stage two small 
corpuscles. It is, however, another matter to prove that these corpuscles 
fuse to constitute a single large corpuscle, such as may be found in 
other cells of the same preparation in which no evidence of fusion 
having occurred can be observed. 
According to these authors, a spindle formed of very fine parallel 
threads constitutes the connecting strand in the division of what they 
term the nuclei in sporulation. I have never been able to observe such 
a structure, but it is possible that what is found in the varieties of 
yeast used for observing it by Janssens and Leblanc, may permit the 
demonstration of such a spindle more readily than in the forms I em- 
ployed. I must say, however, that in S. Ladwzg7zz, employed by them 
also for this object, I was unable to find anything resemble a spindle of 
fine threads. 
I found ina number of cells of S. cerevzsz@,a structure which resembles 
very much that described by Janssens and Leblanc,.and compared by 
them to acell plate. It was a line formed of delicate, closely placed 
granules running transversely to the strand connecting the two 
developing corpuscles and completely dividing the cell into two halves. 
The dotted line was in the majority of cases so fine and so difficult to 
see properly that it required the best illumination and the highest 
available magnification to bring it out. Whether it is to be regarded 
as a cell plate cannot at present be determined. 
The division found in sporulation can scarcely be described as a 
simple form of karyokinesis. It is rather to be compared to the 
division of a chromatic filament in the formation of two chromosomes. 
A more analogous case is that of the division of the nucleolus in 
Euglena viridis, as described by Blochman and Keuten’. In this form 
the nucleolus, at the commencement of division, does not disappear as it 
ordinarily does in other cells, but remains in all the stages. When the 
chromosomes which are formed in the normal way begin to constitute 
the dyaster stage, the nucleolus elongates into a dumb-bell figure, the 
constriction first observed deepening, until complete separation of the 
spherical ends takes place. Each of these passes into the corresponding 
daughter nucleus. In this case, while the ordinary chromatin of the 
nucleus undergoes division by the karyokinetic method, the nucleolus 
undergoes direct division. In sporulation in Saccharomyces it is difficult 
1 **Ueber die Kerntheilung bei Euglena.” Biol. Centralbl., Vol. XIV, p., 194, 1894. 
2 ‘* Die Kerntheilung von Euglena viridis Ehrenberg.” Zeit. fiir Wiss. Zool., Vol. LX, p. 215, 1895. 
