SEXUAL REPRODUCTION. 171 
they give rise to tubular or vesicular germs, which, without 
being much elongated, produce zoospores.* 
De Bary has claimed for the oogonia in Cystopus and Perono- 
spora a kind of fecundation which deserves mention here.+ 
These same fruits, he says, which owe their origin to sexual 
organs, should bear the names of oogonia and antheridia, ac- 
cording to the terminology proposed by Pringsheim for analo- 
gous organs in the Alge. The formation of the oogonia, or 
female organs, commences by the terminal or interstitial swelling 
of the tubes of the mycelium, which increase and take the form 
of large spherical or oboval cells, and which separate themselves 
by septa from the tube which carries them. Their membrane 
encloses granules of opaque protoplasm, mingled with numerous 
bulky granules of colourless fatty matter. 
The branches of the mycelium which do not bear oogonia 
apply their obtuse extremities against the growing oogonia; 
this extremity swells, and, by a transverse partition, separates 
itself from the supporting tube. It is the antheridium, or male 
organ, which is formed by this process ; it takes the form of an 
obliquely clavate or obovate cellule, which 
is always considerably smaller than the 
oogonium, and adheres to its walls by a 
plane or convex area. The slightly thickened 
membrane of the antheridia encloses proto- 
plasm which is finely granular. Itis seldom 
that more than one antheridium applies 
itself to an oogonium. 
The two organs having together achieved a ee ee 
their development, the large granules Con- Peroaospora; a. anther 
tained in the oogonium accumulate at its %™ (Me Bary.) 
centre to group themselves under the form of an irregular 
globule deprived of a proper membrane, and surrounded by a 
bed of almost homogeneous protoplasm. This globule is the 
gonosphere, or reproductive sphere, which, through the means of 
1 De Bary, in ‘¢ Annales des Sciences Naturelles” (5"° sér.), vol. v. (1866), 
p. 343; Hoffimcister’s ‘* Handbook ” (Fungi), cap. v. p. 155. 
+ De Bary, in ‘‘ Annales des Sci. Nat.” (47° sér.), vol. xx. p. 129. 
