380 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
from the wall of the oogone by vacuolization of the parietal layers. 
The beak of the oogone becomes perforated by the absorption of the 
swollen portion of the membrane; and the periplasm then flows out 
through the opening as a drop of mucilage which may contain a nucleus. 
In the young oosperm the chlorophyll-bodies become transformed into 
brown bodies, the process being similar to that which takes place in the 
antherozoids of the Fucaceas. 
Development of Hydrodictyon.* — According to M. A. Artari, the 
chromatophore in the cells of Hydrodictyon utriculatum is not granular, 
but forms a perforated and deeply lobed parietal plate, which becomes 
eventually very thin and reticulate. The mature cell is multinucleated, 
and the “ light patches ” are the nuclei seen through the chromatophore. 
Each nucleus subsequently forms a part of a megazoospore, these being 
formed by the breaking up of the chromatophore, and finally acquiring 
their vibratile cilia ; each megaspore at this time contains a pyrenoid. 
The microzoospores (gametes) are formed in the same way as the mega- 
zoospores, the only difference being in their relative size and number. 
Fungi. 
Histology of Fungi, t — M. P. A. Dangeard has investigated the 
minute structure of Fungi belonging to the following families, especially 
with regard to the occurrence and number of nuclei : — Synchytriacem, 
Olpidiacem, Chvtridineae, Ancylistese, Saprolegniaceae, and Perono- 
sporaceae ; also Spumaria among Myxomycetes. A new genus Hesticu - 
laria is described, belonging to the Ancylisteae, nearly allied to 
Lagenidium and Myzocytinm ; II. nodosa is endophytic in Lyngbya 
sestuarii. The following are some of the more important conclusions 
arrived at. 
The nuclei are most often limited by a double achromatic membrane ; 
in the centre is a spherical nucleole which stains strongly with haema- 
toxylin, being composed almost entirely of chromatin. Between the 
membrane and the nucleole is a more or less dense hyaloplasm, inclosing 
granulations, some at least of which consist of chromatin. The size of 
the nucleus varies greatly, the most frequent being between 1 and 5 /x ; 
in Synchyirium it is much larger. In the young sporanges, cysts, spores, 
and zoospores, each cell contains a single nucleus ; at a later period, 
especially in the vegetative cells, the number is often very large. The 
structure of the nucleus is subject to certain variations. The nucleole 
may be very minute or altogether wanting, when the nucleus is reduced 
to a simple vesicle with aqueous contents; the hyaloplasm may be 
destitute of granulations. 
The mature sporanges and conids contain a definite number of 
nuclei, the number of zoospores being the same as that of nuclei, while 
each spore may contain several nuclei. The cysts are uninucleated. 
The nucleation of the oosphere varies greatly in the different 
families. In Ancylistes Clt>sterii the oosphere has, at all its stages, 
several nuclei,, and the antherid is also plurinucleated. In Saprolegnia 
Thuretii the oogone includes a large number of nuclei ; but those become 
* Bull. Soc. Imp. Nat. Moscou, 1890, pp. 269-87 (1 pi.), 
t Le Botaniste (Dangeard), ii. (1890) pp. 63-149 (2 pis.). 
