STUDIES IN SPERMATOGENESIS AND APOGAMY IN 
FERNS. 
RUTH F. ALLEN. 
During recent years, the interest in the cytology of the ferns 
has developed along two main lines—the study of the male 
cells, for which the ferns are very favorable, and the study of 
apogamy, a field in which ferns also offer excellent opportuni¬ 
ties for the investigation of the important cytological questions 
involved. 
The literature relating to the structure and development of 
the motile male cells is very extensive and has been frequently 
summarized in recent years. I shall here review only the 
papers most closely related to my own studies. 
The early work was done with the aim of determining 
whether the entire cell or only the nucleus entered into the 
formation of the antherozoid. At the close of the eighties it 
was fairly well established that the spiral body of the anthero¬ 
zoid was formed from the nucleus and that the cilia and the 
vesicle were derived from the cytoplasm. The question of the 
presence of a cytoplasmic envelope about the spiral nucleus was 
still under debate. 
G-uiguard (43) in 1889 studied the metamorphosis of the 
mother cell into a spiral antherozoid in Chara, Pellia, Sphag¬ 
num, and Angiopteris. In Angiopteris, the large nucleus 
moves to one side of the cell and elongates into a crescent lying 
against the surface of the cell. The nucleole disappears and 
the chromatin becomes dense and homogeneous. The cilia orig¬ 
inate from a special hyaline layer on the surface of the cell. 
The nucleus now elongates further, becoming transformed to a* 
