Wolfe. — Cytologiccil Studies on Nemalion. 617 
37-44), while after the disappearance of the granules in question its 
size becomes greatly increased. The condition just described, in which 
the nucleus is surrounded by granules (Figs. 46-48), is seen at the 
time when the contents of the antheridium are discharged into the 
water as a naked or thin-walled mass of protoplasm ; and although 
the terms antherozoid, pollinoid, and spermatium, have been variously 
applied to it, the subsequent history seems to indicate that it may more 
properly be termed an antheridium. Since hundreds of instances of such 
antheridia showing these conditions are presented in almost any well- 
stained preparation, it would seem that the arrangement persists for 
a considerable period. At the time, however, when the spermatium has 
reached the trichogyne these granules have usually disappeared (Fig. 16) 
and the nucleus has resumed its normal appearance, although, as already 
mentioned, the nucleolus has undergone a conspicuous increase in size. 
That the so-called spermatium cannot be regarded as a sexual element, 
but, as just noted, is to be homologized with the antheridium, is shown 
by the fact that a rapid division into two sperm-cells now takes place 
(Figs. 49, 50), which, so far as it has been possible to determine, is an 
invariable preliminary to actual fecundation, and takes place shortly 
after conjugation with the trichogyne. The figure in this mitosis is of 
the type already described, and, so far as could be certainly determined, 
presents no unusual features. In several cases the number of chromosomes 
could be fairly well estimated, and is certainly very close to the number 
eight, which is seen in the preceding mitosis. From the above facts it 
would appear that, although the term spermatium might be conveniently 
retained in conformity with previous usage, it should be distinctly under- 
stood that it is not the homologue of a sexual element. 
It should be mentioned that a binucleate spermatium has been de- 
scribed by Schmidle (’ 99 ) in his paper on Batrachospermum , but he leaves 
us somewhat in doubt as to when and how this division occurs, which is 
of importance, as Osterhout (’ 00 ) found this body in the same genus to 
be uninucleate and suggests that a binucleate appearance is probably 
due to disorganization. Further, Davis (’ 96 ) noted the rare occurrence 
of a binucleate appearance in the spermatium of this plant, assuming, 
however, that they were fragmentation-products. In presenting the 
mitotic figures from which these two nuclei arise, and which are of very 
common occurrence, the writer believes that he has established the fact 
that this binucleate condition is a normal phenomenon. 
Fertilization and Development of the Cystocarp. 
The trichogyne, as has been stated above, contains at this time no 
organized nucleus. Both the male cells, as we have already seen, seemed 
normally to be discharged into the trichogyne. The processes of ferti- 
