166 BOTANICAL GAZETTE | SEPTEMBER 
expected from ontogeny, since the conditions prevailing during 
oogenesis are such that any vestigial attempt to individualize 
gametes from the nuclei would be at once obliterated. Naturally 
the individualization of gametes would without doubt become 
quickly eliminated from ontogeny after fertilization en masse 
became a fixed habit. Perhaps some one of the other eight 
species of Albugo may exhibit in the oogonium vestigial traces 
of older conditions and a more perfect individualization of 
gametes, as the conidia in many Peronosporineae develop 
zoospores which later merge their individuality into a common 
mass of protoplasm when the conidium germinates by means of 
atube. If the multinucleate sex cells were primitively multi- 
nucleate, if there has been an independent line of development 
starting with multinucleate zoospores and leading through multi- 
nucleate isogamous gametes to the coenogamete, it might be 
expected that some structures indicative of such evolution would 
now be found among living plants. But there are no stages of 
such a character known, nor is there any group among the algae 
or fungi which promises to supply them. Possibly the most sug- 
gestive group is the Monoblepharadineae, which has recently been 
investigated by Lagerheim (1899), who finds only one nucleus 
in the rudimentary oogonium, and as many nuclei in the antherid- 
ium as there are sperms to be formed. There is much evi- 
dence, however, to support the hypothesis that the coenogamete 
is homologous with many gametes, which have failed to separate. 
This hypothesis postulates an origin from uninucleate, swarming 
gametes, generally present in coenocytic algae, as Hydrodictyon 
(Artari 1890), Dasycladus (Berthold 1880), Acetabularia 
(DeBary and Strasburger 1877), Protosiphon (Klebs 1896), 
not Botrydium (Rostafinski and Woronin 1877) as is so often 
erroneously cited,’ thus showing the prevalence of this mode of 
sexuality among the algae that are usually looked to for the 
ancestry of the Phycomycetes. The elongation of the sperm 
nuclei as they lie in the antheridial tube may also be regarded 
as indicative of an ancestry in which each nucleus was the 
* For the most recent work on these species see Iwanoff, 1898. 
een pene paar 
