465 
The Conjugation of the Infusoria. 
origin of the functional one. This abortive gamete (d 1 ) 
corresponds, if anything in the conjugation of the Infusoria 
does so, to one of the polar bodies formed in oogenesis, i.e. 
as a rudimentary gamete. It will be noted that it also has 
its abortive equivalent in the micro-zooid (d 2 ). Regarding 
the phenomena in the latter prior to actual conjugation, 
an apparent stumbling-block is met with in the fact of the 
occurrence of three divisions of the micro-nucleus instead 
of two. 
There might have been some hesitation in explaining away 
the first of these, were it not that Maupas, who is justified 
more than any one else in expressing an opinion on the 
matter, had already given a verdict favourable to all my 
desires. He regards the first division of the three, which also 
happens in both the conjugating individuals of Euplotes patella , 
as a formation of two micro-nuclei. The reasons assigned 
may be found in his memoir as cited below 1 . Leaving the 
first division out of account, as Maupas has also done, we have 
then in the micro-zooid two divisions B and C, which may 
be interpreted as spore-formation and reduction. Of the 
eight spores (e) only one is functional. It, like the corre- 
sponding sporo-zooid of the macro-zooid, divides once (D) and 
the abortion of one of its products, or gametes ( d 2 ), has 
already been commented upon, and the obvious reasons given. 
At the time of writing the present paper it is quite out of 
question to construct diagrams from Maupas’ accounts of the 
conjugation of other forms, which he has studied, but of 
which he has furnished no schemes. And the risk must be 
taken of postponing another study of the whole of his im- 
mense monograph, until more leisure is available. It might 
well happen that some details of the explanation of his 
results here suggested may have already been put forth by 
Maupas himself. If so, there is neither wish nor intention 
of detracting from his merits. What has really been my 
concern was the demonstration of an antithetic alternation of 
generations and of a spore-formation with reduction in the 
1 p. 364 and p. 341. 
