254 THE AMERICAN NATURALIST. (Vot. XXXIX. 
Harper that the number of chromosomes presented in the 
mitoses within the ascus is large (8, 12, 16, in various species) 
as against Dangeard and Maire who have claimed that the 
number is uniformly 4. Guilliermond's account of spore forma- 
tion in the ascus supports that of Harper (described in Section 
II) in all essentials and gives especial attention to the structure 
of the epiplasm and its inclusions. 
In summary : the significance of the nuclear fusions in the 
ascus seems very much of a mystery. If they could be associ- 
ated with an apogamous development of the ascocarp we should 
have conditions analogous to those in the Basidiomycetes but 
following a sexual act as it does in Sphzerotheca, Erysiphe, and 
Pyronema we find a phenomenon whose raison a’ étre is not 
apparent. However, we do not know the history of the nuclei 
preceding the group of four at the end of the ascogenous hypha 
and perhaps it may be discovered that events at this period are 
concerned with nuclear reduction at the end of a sporophyte 
generation. 
One of the most interesting announcements of recent months 
is that in a preliminary note of Farmer, Moore, and Digby (:03) 
on the nuclear history preceding the apogamous development of 
a species of Nephrodium. They found that the cells of the 
prothallus at the point where the sporophyte arose became 
binucleate by the migration of nuclei from neighboring cells. 
The two nuclei might remain separate for some time or fuse at 
once, The authors speak of the whole process “as a kind of 
irregular fertilization" and Blackman considers it analogous to 
the entrance of the nucleus into the fertile cell of Phragmidium 
and the establishment of the paired nuclei in the Uredinales. 
As we discussed the phenomenon in that connection I consid- 
ered the use of the term fertilization unfortunate since it 
included processes which however similar physiologically held no 
relation morphologically and phylogenetically to normal sexual 
processes. As stated then, it seems to me much clearer to 
regard all such apogamous phenomena apart from sexual proc- 
esses, pointing out as far as possible physiological resemblances 
but recognizing the wide gap in morphology established by the 
past evolutionary history of the plant. The interest in the phe- 
