20 



joined to the sphere; they spring from the parts of the external membrane which were 

 at the poles of the ascospore. 



FIG. 8-9. - - View of the sphere produced by the growth of the germinal ampulla 

 (this is the oogone} and of the hemispherical calottes (antheridies) which come from one 

 part of the external membrane of the ascospore. The oogone is coloured light yellow, its 

 membrane presents, on the exterior, a very finely shagreened aspect. The antheridies are 

 completely freed of the brown matter and of the prickles which covered over the cellular 

 layer of the external envelope of the spore. The colour of the antheridies is light yellow 

 after the colour of the cells which compose their coating. 



FIG. 10. -- The oogone and the antheridies seen in section : one can distinguish the 

 openings which have been made in the membrane of the oogone and which allow of 

 communication between the latter and the antheridies. The antheridies circumscribe a 

 cavity between their coating and the membrane of the oogone. 



FIG. 11-12. -- Development of the egg in the oogone. 



FIG. 13. - - The oogone containing an egg; in the centre of the egg is found a cavity 

 indicating that the egg has been developed by the growth of a filament, which has increased 

 in every direction, by bending over. The antheridies have become detached; on the cir- 

 cumference of the membrane of the oogone may be distinguished three openings whence 

 will issue the germinal filaments sent out by the egg : two of these openings commu- 

 nicated with the antheridies. 



FIG. 14. A free oogone before the formation of the egg. 



FIG. 15. The oogone and the antheridies seen transparently; in the interior, a fully- 

 developed egg. The cells of the egg, regular and oval-shaped, appear as spores ; this 

 aspect is caused by an optical illusion, for the filaments are seen in diameter; it is, indeed, 

 possible to see certain filaments longitudinally, by causing the point to vary. 



There may be seen, transparently, under the membrane of the antheridies, the two 

 openings of the oogone opposite to the antheridies : a central opening is also formed at 

 the exterior of the oogone. 



The egg is brought together again at the centre of the oogone and leaves all around 

 an empty space in the oogone. 



FIG. 16. An egg in which may be seen the terminal filaments, all mixed up (germi- 

 nal filaments). 



FIG. 17. The central opening of the oogone; there may be several of these, without 

 counting those of the antheridies. 



FIG. 18. An oogone of very small dimensions, from which issue the germinal fila- 

 ments which are the terminal ramifications of the egg. 



FIG. 18' and 18". - - The same oogone seen transparently, at different planes, so 

 as to allow of one's observing the constitution of the egg which is very simple. 



FIG. 19. -- Small spherical bodies, regular and yellow, coming from the crushed 

 oogone : they seen to be oospheres. They are bound together by a delicate and extre- 

 mely thin ligament. 



