Marquette—Spore Mother-Cells of Marsilia. 95 
it seems probable, however, that the difficulty in distinguish¬ 
ing the nuclear membrane here is due to the over- and underly¬ 
ing dense starch mass; at any rate the starch mass will give such 
an appearance as is found even if the nuclear membrane is of 
uniform thickness throughout. 
The fact that the spore mother-cells of Marsilia show a dis¬ 
tinct polar organization from an early period in their develop¬ 
ment, makes it seem likely that the forming spindle should be 
bipolar from the beginning of its appearance, an expectation 
which is increased by the early appearance of a bipolar ar¬ 
rangement of the fiber groups in the cytoplasm. A study of 
the spore mother-cells at the time when the nuclear membrane 
has just disappeared shows, however, that apparently this ex¬ 
pectation is not realized. The spindle fibers, which by that 
time have assumed the smooth, clean-cut appearance charac¬ 
teristic of the fibers as found in the completed spindle, are not 
arranged in a bipolar figure, but in several perfectly distinct 
and separate poles. The spore mother-cells of Marsilia show 
as striking “multipolar” spindles as are found anywhere. .Fig¬ 
ures 9 a and 9 h represent two consecutive sections of a spore 
mother-cell with four well-developed poles; 9a lies above 9 h, 
and the starch mass lies in the section above that from which 
9a is taken. Fibers from each of the four poles run up to the 
chromosomes, and in addition there are some running more 
or less continuously from one pole to another; this is to be 
seen in the two lower poles of the cell figured. There are also 
some fibers connecting the other poles, but they are not so 
numerous nor so conspicuous. The idea suggests itself, but it 
is only a suggestion, that the two poles conspicuously connected 
by fibers will be the definitive spindle poles. One of the four 
poles lies in close contact with the plasma membrane, two 
others have at least some fibers running up to the plasma mem¬ 
brane, and the fourth one lies distinctly free from it, although 
it comes close to it. That this pole is not in contact with the 
plasma membrane in a plane above or below that of the draw¬ 
ing can be easily determined by focusing up and down. 
It is a fact worth noting that many of the “multipolar” 
spindles which have been figured are quadri- and tripolar 
