632 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
the oosphere may be termed megagametes (macrogametes), the much 
smaller male individuals microgametes. Both kinds arise, after many 
non-sexual generations, the former by division of the non-sexual cells into 
two or four, the latter by division into four or eight. The former vary 
between 20 and 29 /a, the latter between 9 and 15 /a in size ; both 
closely resemble the non-sexual individuals, but are somewhat more 
elliptical, and possess a distinct double membrane. Conjugation was 
never observed between gametes of the same kind. A mega- and micro- 
gamete unite by their narrower ends, and continue in motion for a con- 
siderable time, often more than an hour ; they then lose their flagella 
and come to rest. While still in motion, the contents of the male cell 
begin to move towards its anterior portion, and gradually pass over 
entirely into the anterior portion of the female cell through a canal 
which connects the two with one another. The protoplasts and the two 
nuclei unite completely, but not the pyrenoids and chromatophores. 
The product of conjugation becomes rounded off and excretes a coat of 
cellulose. The author compares this process of conjugation to that 
which takes place in the Zygnemaceee. The gradual coalescence of the 
two nuclei can be easily followed in a hanging drop, even without the 
use of staining-reagents. A cellulose-reaction was in a few cases 
observed in the membrane of the gametes. The zygotes are usually 
enveloped in a brownish granular mucilaginous substance. Their con- 
tents break up into two, and eventually into four or eight, non-sexual 
flagellated individuals. 
Chlamydomonas Braunii has also a palmella-condition, which can be 
readily cultivated in a moist chamber, and is then indistinguishable 
from colonies of Pleurococcus or Gloeocystis ; from these the non-sexual 
flagellated individuals are again developed. 
Hariotina.* — Prof. A. Borzi identifies Dangeard’s Hariotina reticulata 
with Coelastrum verrucosum (Reinsch) De Toni. It consists of colonies 
of four, eight, or sixteen spherical cells ; each cell has a chromatophore 
in the form of a parietal plate inclosiug a pyrenoid. It is propagated 
by zoospores, from sixteen to thirty-two being formed in each cell, in 
the same way as those of Hydrodictyon and Pediastrum. 
Fungi. 
Nucleus of the Oomycetes during Fecundation.f — M. P. Dangeard 
has investigated the appearance of the nuclei of the sexual elements in 
cellular Cryptogams, and particularly in Fungi. He points out that 
with care two cases can be distinguished, the one in which the sexual 
elements are uninucleated, and the other where they are plurinucleated. 
An example of the first is afforded by Basidiobolus rannrum , in which 
simple fusion takes place, analogous to the fecundation of the Conjugates 
and Chlamydomonadinese, among Algae. The second case, however, is 
much more common among Fungi, in which the vegetative and repro- 
ductive cells are plurinucleated. The nuclei of the oospheres can be 
easily observed until the time of communication with the antherids ; but 
they then disappear, and either assist in the formation of the oosperm 
* La Nuova Notarisia, 1891, pp. 382-4. Cf. this Journal, 1890, p. 489. 
f Kev. Mycol., xiii. (1891) pp. 53-5. 
