104 
angium, and that from these sixteen cells the final spores are 
formed. The stage between the first spore cell and the sixteen 
cells is directly comparable with the “ division-period ” in animal 
maturation. The sixteen-cell stage (see next page) is the stage of 
enlargement and of tetrad-formation and corresponds with the 
“srowth-period.” Finally the “ maturation-period”’ is recognized 
by the two consecutive divisions of the sixteen cells to form the 
sixty-four spores. 
As the maturation phenomena are so closely parallel in plants 
and animals, it would be of advantage to have the corresponding 
cells designated by analogous names. In some cases the present 
botanical names are unwieldy and inappropriate. The ‘ spore- 
mother-cell” as a designation for the cells of the sixteen-cell stage 
is incorrect as well as clumsy; for, if we consider the nuclei alone, 
these cells do not give rise to the spores, but to the “ mother-cells ” 
of the spores, and are therefore the “ grandmother-cells” of the 
spores. I propose, therefore, to use the term ‘‘ primary sporocyte”’ 
for the cells of the sixteen-cell stage, and “ secondary sporocyte ” 
for cells of the thirty-two-cell stage. These terms are directly 
analogous to “ primary” and “ secondary” “‘ odcyte,” and “ sperma- 
tocyte” in animal cells. The term ‘‘sporogonium,” which in this 
connection would be analogous to the term “ odgonium ” or “ sper- 
matogonium ” is, unfortunately, already used in a different sense 
in botanical nomenclature and | shall therefore designate the first 
eight cells in spore formation as ‘‘ archesporial cells” in accordance 
with botanical usage. 
C. Observations. 
It is beyond the scope of this paper to describe in detail the 
formation of the sporangium, with its annulus and tapetum, or 
to describe the degeneration of the tapetal cells. Nor is it neces- 
sary to give aminute account of the mitoses leading up to the 
formation of the sixteen sporocytes. They all agree with the 
division of the “ archesporium” and the number of the chromo- 
somes apparently remains the same, although they are so numer- 
ous that it is impossible to give the absolute number. From care- 
ful counting in several cases, I estimate the number to be between 
one hundred and twenty and one hundred and thirty. 
The unicellular archesporium, which is destined to give rise to 
