The Cytology and Life-history of Nemalion 
multifidum, Ag. 1 
BY 
RALPH E. CLELAND. 
With Plates XXII— XXIV and three Figures in the Text. 
Introduction. 
HE cytological situation in those red algae which develop tetraspores 
JL has become in the past few years fairly clear. The seat of chromosome 
reduction has been accurately determined as being in the tetraspore mother- 
cell, and the life-histories of several of the representative forms have been 
worked out. The conclusions from cytological investigations have received 
striking support from experimental cultures (Lewis, 1912 £,1914), which 
have shown that sexual plants come from tetraspores and tetrasporic plants 
from carpospores ; these two phases alternating in the life-history. The 
situation, however, in those forms which do not produce tetraspores, has not 
been thoroughly ascertained. The results obtained by Wolfe (1904) on 
Nemalion multifidnm , and Svedelius (1915) on Scinaia furcellata , are con- 
tradictory and the group as a whole needs thorough investigation. 
In the hope that I might be able to throw some light upon this situation, 
work was begun on Nemalion during the summer of 1916. The investiga- 
tion has been carried on at the University of Pennsylvania, and at the 
Marine Biological Laboratory, Wood’s Hole, Mass., under the direction of 
Prof. Bradley M. Davis. I wish to take this opportunity of thanking 
Dr. Davis for material, and for the constant help and criticism that he has 
so willingly given. I am also indebted to Professors George T. Moore and 
Ivey F. Lewis for much sympathetic assistance extended to me at Wood’s 
Hole. Since the work was undertaken, a short paper on Nemalion by 
Kylin (1916 c) has appeared. A number of his results I have been able to 
verify. 
Methods and Material. 
Some of the material used in this investigation was collected by 
Dr. Davis in the summer of 1908 off Gay Head, Mass., and fixed by him 
in weak Flemming. This proved to be very well fixed. The rest of the 
1 Contribution from the Botanical Laboratory of the University of Pennsylvania. 
[Annals of Botany, Vol. XXXIII. No. CXXXI. July, 1919-] 
