12 Wisconsin Academy of Sciences, Arts, and Letters. 
rspectively. If cultures of prothallia are placed in strong light 
and watered from below, fertilization is prevented and apoga- 
mous outgrowths form instead. These sporophytes develop 
from a single surface cell of the prothallium and the chromo¬ 
some number remains sixty-six. Here, then, is a second case 
(Lastraea pseudo-mas being the first) in which the chromosome 
number present in the gametophyte persists during the develop¬ 
ment of the sporophyte. 
I have studied the development of the antherozoids in Adian- 
tum and Aspidium falcatum and the apogamous development 
of the latter species, Prothallia of A diant um Capillus-V eneris 
were purchased. The prothallia of Aspidium were grown in 
pots of red clay. The pots were covered with bell jars or were 
kept in a Wardian case and surrounded by Sphagnum or moist 
sand. The prothallia were not watered from above. The 
moisture in the sand or Sphagnum provided the clay with a 
uniform supply. Material for sectioning was fixed in the dif¬ 
ferent Flemming’s solutions. The solution of medium strength 
gave the best results. The sections were stained in the triple 
stain or in Heidenhain’s iron-haematoxylin. 
The material for sporogenesis in A. falcatum was taken from 
vigorous green house plants. Flemming’s medium solution, 
picro-formol solution, and a mixture of one-half glacial acetic 
acid and one-half absolute alcohol were used for fixing. Sec¬ 
tions were stained in Flemming’s triple stain or with Heiden- 
hain’s iron-haematoxylin. 
The Development of Antherozoids in Adiantum Capil¬ 
lus-Veneris and Aspidium falcatum. 
The dome-shaped mother cell from which the antheridial sac 
arises has a volume nearly equal to that of the entire sac, just 
after nuclear and cell division is completed. At the end of 
this period of active division there ensues a considerable period 
of growth during which the diameter of each antherid (or 
antherozoid mother cell) is nearly doubled. 
One would naturally expect under such circumstances to 
find a typical resting nucleus in the growing cell. Yet a true 
