ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
719 
spores. The exact structure of the swarm-spores could not be determined. 
A peculiar mode of conjugation between two resting-spores was in some 
cases observed. The whole course of development the author believes 
to be as follows: — The resting spore becomes, after hibernation, a 
swarm-forming cyst, from which escape a number of small zoospores 
which penetrate into the Vaucheria filament. Here they pass into an 
amoeboid condition. The amoebae are nourished by the chlorophyll and 
other contents of the host, and develope into large plasmodes, which 
subsequently divide. These fragments then round themselves off, and 
become cysts with very thin membranes. In these thin-walled cysts a 
number of swarm-spores are produced, which escape into the surrounding 
water. These penetrate into other Vaucheria filaments, and the cycle 
of development is complete. 
The property which Woronina possesses, in its plasmode stage, of 
taking up solid substances by means of pseudopodes, and of excreting 
the undigested ingesta, appears, to the author, to determine its position 
in the animal rather than in the vegetable kingdom. He places it in the 
family of Monadineae zoosporeae, which he divides into three groups, 
the Pseudosporeae, Gymnococcaceae, and Plasmodiophorae, of which 
Woronina belongs to the second. 
Brefeld’s Mesomycetes.* — Prof. W. Zopf adduces arguments against 
the system of Brefeld which establishes, as a primary group of fungi, 
the Mesomycetes, again divided into the Hemiasci and Hemibasidii 
(Ustilagineae). He contests Brefeld’s assertion that the structure which 
De Bary calls promycele in the Ustilagineae is, in reality, of the nature 
of a basid ; there are, in fact, a large number of forms in which it is 
altogether wanting. He disputes also the validity of the distinction 
drawn by Brefeld between the ascus of the Aseomycetes and the sporange 
of the Phycomycetes, from the constancy or inconstancy of the number 
of spores. There are many Aseomycetes in which the number of the 
ascospores in the ascus is inconstant, and many Phycomycetes in which 
the number of spores in the sporange is constant. 
Sexual Reproduction in the Ustilagineae.f — M. P. A. Dangeard 
has further studied this subject in the case of Entyloma Glaucii. The 
fusion of the two nuclei within the oogone was clearly observed ; they 
are suspended in its centre by trabecules of protoplasm ; at the spot 
where they come into contact with one another the two nuclear mem- 
branes disappear, and the two nucleoles subsequently coalesce. The 
oosperm then contains a single central nucleus ; the protoplasmic trabe- 
cules form large vacuoles, and the membrane becomes stratified into two 
layers. 
Sexual Reproduction among the Ascomycetes.f— M. P. A. Dan- 
geard has pursued his investigations on this subject, both among the 
Exoasci and the Carpoasci (Discomycetes, Pyrenomycetes, and Peri- 
* Beitr. z. Phys. u. Morph, niederer Organismen (Zopf), Heft 3 (1893) pp. 1-14 
(4 figs.). Cf. this Journal, 1892, p. 400. 
f Le Botaniste (Dangeard) iv. (1894) pp. 12-7 (3 figs.). Cf. this Journal, ante , 
p. 485. 
X Le Botaniste (Dangeard) iv. (1894) pp. 21-58 (10 figs.). Cf. this Journal, ante, 
p. 486. 
