CELL-DIVISION IN THE SEX CELLS OF TAENIA 22l 
nuclei if they have arisen by the process of amitosis. The same 
statement will apply to the nuclei shown in figure K of the same 
plate. If we assume on the other hand that nuclear division has 
taken place by mitosis the condition shown in figure A offers 
an explanation for the condition figured in K and L. In the 
process of reconstruction the nuclei have come to lie in close 
contact. The sister nucleus of at least one of these nuclei is in 
another section of the same ovum. 
COMPARISON WITH MONIEZIA 
When I had almost concluded my work on Taenia, I received 
some of Dr. Richard’s slides of Moniezia.*’ The examination of, 
these slides shows that the character of cell-division in Moniezia 
is for the most part similar to that of Taenia. The figures of 
plate 8 have been taken from Moniezia. They show late seg- 
mentation and the cell boundaries are not visible. Early cleav- 
age takes place by mitosis and the blastomeres are distinct. 
Later, as Child (’11) states, the cell boundaries become less dis- 
tinct and entirely disappear, giving rise to a syncytial condition. 
When the cell boundaries are distinct (in the early cleavages) 
in Moniezia, the nuclei do not lie in contact nor is there any con- 
dition which indicates that cell-division has taken place by ami- 
tosis. Later, when the cell boundaries have disappeared, numer- 
ous cases of nuclei which lie in contact are found, and sometimes 
they are so close together that the surfaces between them are 
flattened. The unquestionable cases of mitosis are fewer in 
these regions, but that mitosis does take place here is shown in 
figures B, D, and E.. In Taenia, where, in the early cleavages, 
the ovum is a syncytium, nuclei may lie in close contact any 
time after the first cleavage, as has already been shown. 
Since, among the slides of Moniezia, that I have examined, 
there is only one of the late segmentations, the comparison of the 
length and position of the spindle has not been made, but the 
reconstruction of the nucleus is similar to that of Taenia. The 
nuclei in the process of reconstruction shown in figure E, plate 
41 take this opportunity of expressing my indebtedness to Dr. Richards for 
his kindness in loaning me these slides. 
