GAMETOGENESIS AND FERTILIZATION IN ALBUGO. 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY. 
XXIX 
FRANK LINCOLN STEVENS. 
(WITH PLATES I-IV) 
[Concluded from p. 169.) 
Ill. GENERAL CONSIDERATIONS, 
OBSERVATIONAL evidence that kinoplasm and trophoplasm 
(Strasburger 1892) are true morphological elements of the cell 
has steadily increased, and striking experimental evidence has 
recently been adduced to confirm this conception (Hottes, ined.). 
In 1892 Strasburger proposed a theory of fertilization founded 
upon the assumption that sexual cells are incapable of develop- 
ment, owing toa kinoplasmic starvation. This theory was based 
partly upon observations on Ulothrix, and the relation of the 
cilia in sexual and asexual cells. Much confirmatory evidence 
has since been received, and in Strasburger’s latest book (1900) 
the theory is developed more completely. As applied to sex- 
ually differentiated cells, the theory postulates kinoplasmic hun- 
ger in the female and trophoplasmic hunger in the male. The 
phenomena attending zonation in Albugo and Peronospora are 
capable of explanation in the light of Strasburger’s theory, and 
in turn materially strengthen the theory itself. In Albugo and 
Peronospora the marshaling of the nuclei into a hollow sphere, 
a most conspicuous phenomenon, is quite inexplicable on the 
ground of atavism or phylogeny, nor can it have to do with wall- 
building. Why then do the nuclei habitually leave the ooplasm, 
apparently to perform no useful function in the periplasm, only 
to return and function as female pronuclei ? 
A study of the accompanying plates shows plainly that the 
periplasm is of a distinctly different character from the ooplasm. 
238 [OCTOBER 
