VAUCHERIA. 95 
it wanders toward the center of the odgonium (Fig. 34, C), which is now 
separated from the filament by a cross-wall. The egg-nucleus retains 
this position until fecundation (Fig. 34, D) ; it does not divide and the 
probability of any nuclear substance being thrown off with the extru- 
sion of a small plasmic or mucilaginous mass when the odgonium 
opens is, therefore, excluded. Although Oltmanns observed in the 
cytoplasm of the beak granules staining somewhat more intensely than 
Fic. 34.—Fecundation in Vaucheria clavata.—(After Oltmanns.) 
A, B, young odgonia before being delimited by transverse walls from filament. In B all 
nuclei save one are passing back into filament. 
C, oégonium ready for fecundation. 
D, the spermatozoid has entered egg. 
E, F, sexual nuclei in contact; in F the male nucleus has increased in size. 
G, a fusion nucleus. 
H, odgonium containing déspore several weeks old. 
the rest, yet he does not think it probable that these sustain any rela 
tion to the nuclei. At the upper end of the egg is the rather large recep- 
tive spot formed by the withdrawal of the chloroplasts from that region. 
Immediately on entering the cytoplasm of the egg the sperm-nucleus 
increases noticeably in size; its linin net, now more loosely arranged, 
reveals many strongly-staining granules which are probably chromatin. 
In the meantime the egg-nucleus enlarges considerably, and appears 
