26 MARCUS M. HARTOG. 
Saprolegniex find a parallel in those of Dasycladus 
and Derbesia (supra, p. 18). 
Marshall Ward sought! to identify the extrusion of proto- 
plasm by the forming oospores with the formation of polar 
bodies in the Metazoa; and the resumption of these masses he 
regarded as probably connected with the alleged partheno- 
genesis of the group. The latter view, and indeed the former 
also, break down now that we know that both processes occur 
in the formation of the asexual zoospores; they find their 
explanation in the comparison with the zoospore formation of 
Cladophora. 
(6) Phycomycetes Aplanosporez. 
The Entomophthoree present conjugation between their 
hyphe; as a rule the conjugation takes place in the horizontal 
tube uniting two hyphe, like the cross-bar of an H, and the 
zygote forms a spherical enlargement in the middle. 
Unfortunately we know nothing of the cytology of the 
process in the majority of the species ; it has only been studied 
in Basidiobolus,? which is by exception truly cellular (while 
the other genera are apocytial), and which is peculiar in its 
conjugation. 
In this genus two adjacent cells of a hypha grow out side- 
ways at their adjacent ends, which turn up side by side, and 
the nucleus of each enters its turned-up tip. Either nucleus 
divides by mitosis ; the upper daughter-nucleus passes into the 
extreme tip, and is cut off as a sterile cell; the lower nucleus, 
with all the protoplasm of the cell, fuses with its fellow to 
form the zygote. Here we have the best parallel with polar- 
body formation to be found in isogamous conjugation. If we 
compare this with the conjugation of Closterium or Epi- 
themia (supra, p. 14) we find the interpretation obvious: 
the first cells are progametes, and on approaching produce the 
1 « Observations on Saprolegniez,” in ‘ Quart. Journ. Micr. Sci.,’ vol. xxiii, 
pp. 282 (note) and 291. 
2 By Hidam, in ‘Cohn’s Beitrige,’ vol. iii. 
