152 Darns.— Nuclear Studies on Pellia. 
have been derived from the quadripolar spindle through the 
convergence and fusion of the four centres in pairs. Farmer 
also believes that the quadripolar spindle is associated with 
and conditioned by the peculiar character of the four-lobed 
spore-mother-cell. These are very fundamental and interest- 
ing suggestions whose establishment would be important 
contributions to plant-cytology. 
A quadripolar spindle, such as Farmer has described for 
P allavicinia, whose four centres act simultaneously so that 
the chromosomes separate into four groups, is quite unknown 
in other plants or in animals. It should be investigated with 
great care, for upon the fact may depend much of theoretical 
interest in the problem of the evolution of mitotic phenomena 
in the spore-mother-cell. If the quadripolar spindle merely 
accompanies the curious four-lobed spore-mother-cell of the 
Jungermanniales it may be entirely without morphological 
significance. But the theoretical considerations involved take 
on new interest from the facts of double longitudinal splitting 
of the chromosomes during the first mitosis in the spore- 
mother-cell, described for a number of forms by Guignard (’99) 
( Naias ) and Strasburger (’99). 
The writer has not been able to examine much material of 
P allavicinia, and wishes only to express his fear that Farmer 
may have misinterpreted his preparations. As will appear 
from the present investigation of Pellia , as well as the exami- 
nation of Anthoceros (Davis ’99), the writer holds views on the 
method of spindle-formation in the Hepaticae very different 
from those of Farmer. But results in studies of this character 
come so slowly that one may well hesitate to advance a theory 
covering an entire group. However, after the account of this 
investigation, the reader will find some suggestions in that 
portion of the paper headed £ General Considerations.’ 
The material, Pellia epiphylla , was collected during the 
summer and autumn of 1899 from several localities, but 
chiefly from rocky gorges near Starved Rock, Illinois. The 
mitoses of the spore-mother-cell take place early in October 
so that the spores are fully developed before frost. Indeed 
