‘ 
376 BOTANICAL GAZETTE [JUNE 
still room for entirely new hypotheses, and care should be taken 
lest newer and perhaps better suppositions be rejected by the 
too common appeal to authority. 
Shortly before the publication of my paper on Lilium, but 
not until the investigation had been completed, articles on the 
subject of reduction were published by Calkins (6), Mottier (23), 
and Strasburger (34). Each of these authors presented evi- 
dence favorable to the hypothesis that a transverse splitting of 
the chromosomes occurs during the reducing divisions of the 
plants studied. Miss Sargant (27) had also published a paper 
somewhat earlier, in which some facts were presented favorable 
to the supposition of a transverse division. Calkins, however, 
seems to be the only one of these investigators who has not 
reversed his published opinion. More recently Belajeff (2) has 
.asserted the transverse division, while Stevens (32) holds that 
in the ferns studied by him both divisions which go to form the 
spore tetrad are longitudinal. Guignard (14) has lately also 
published articles on the subject, maintaining that there is only a 
longitudinal division. Atkinson (1) has published the results 
of his investigation of sporogenesis in the anthers of Avzsaema 
triphyllum and Trillium grandifiorum. In the case of Arisaema 
he states that a qualitative division takes place in the first divis- 
ion, while in Trillium it occurs in the second. Duggar (11) also 
believes that a transverse division occurs in the first division in 
Symplocarpus fetidus. In studying the development of the 
microspores of Convallaria majalis and Potomogeton foliosus, Wie- 
gand (35) was unable to determine whether the division was 
longitudinal or transverse, but he inclines to the belief that it is 
transverse in the second division. Thus it appears to be very 
doubtful in which division the reduction normally occurs. | Here, 
as in many other problems of cytology, the personal element is 
still very large. 
The zoologists also report these variations. Paulmier (25), 
in his study of the spermatogenesis of Anasa tristis, says that the 
chromosomes have a twisted appearance, and that the first 
division is transverse and a true reduction division, while the 
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