1901] SPORANGIA AND GAMETOPHYTES OF SELAGINELLA 175 
skeptical of the results obtained by this method of investigation. 
He fails to comment on Heinsen’s statement with regard to the 
method of cell division. Both Arnoldi’s and Fitting’s articles 
have been comparative studies of certain phases of the Selagi- 
nella life history with the same stages of Isoétes. Thus, until 
the year 1900 we have not had a correct interpretation even of 
the parts of the megaspore. 
MALE GAMETOPHYTE.— We are indebted to Millardet's memoir 
for our earliest knowledge of the male gametophyte. This work 
appeared in 1869, and almost no detail of importance has been 
added by later workers. In 1885 Belajeff repeated Millardet’s 
work on the same species and corroborated all essential details. 
There has been no other during the last sixteen years until the 
present account given in this paper of S. agus. How much the 
discrepancies between the two are due to differences in methods 
of technique, rather than to specific characteristics, remains to 
be demonstrated. Millardet and Belajeff both examined the 
microspores of several species of Selaginella (S. Avaussiana, 
stolonifera, and cuspidata) in living condition, then added various 
reagents to the microscope slide, focusing through the spore 
coats or crushing them by pressure of the cover glass, to deter- 
mine the phenomena taking place within. The material for the 
account of the male gametophyte of S. apus was killed, imbedded, 
sectioned, and stained without removing the spores from the 
strobilus. It will be seen that the main difference lies in the 
fact that in the earlier accounts there are eight cells described 
which constitute an antheridial wall; that later these cells dis- 
appear, and the sperm cell complex floats free in the cavity thus 
formed. Both authors state that they were unable to secure a 
cellulose reaction for the cell walls. On the other hand, I could 
demonstrate the presence of no such walls in S. apus. The first 
division of the spore results in two free cells. The first, accord- 
ing to Pfeffer’s and Millardet’s view, is the reduced vegetative 
part of the prothallium. The latter, which I have called the 
generative cell, divides at once into a complex of sperm cells. Is 
it possible that the protoplasmic films surrounding the vacuoles 
