500 
MONTGOMERY. 
[Vol. XV. 
forty ; and in Piscicola , usually one in the ovum and the 
ganglion cells, about twelve in the mature muscle cells, and 
three hundred or four hundred in the subcuticular gland cells. 
From the data at hand we accordingly conclude that the 
number of nucleoli is not constant for the species. (On the 
number of nucleoli at different stages in amphibian ova, cf. Car- 
noy and Lebrun, ’ 97 a). 
In order to determine whether the number of nucleoli in egg 
cells were fixed for, or in any way determined by, the particular 
groups of Metazoa, I have compiled the following tables (pp. 501- 
505) for the larger groups, these tables representing the data 
of previous investigators and of my own observations. In them 
four classes of germinal vesicles are distinguished according to 
differences in the number and kind of the nucleoli; this classifi¬ 
cation is only for convenience’ sake, only arbitrarily chosen, and 
is probably not a natural one. On the left hand is given the 
name of the genus or group ; the asterisk corresponding to each 
form indicates by its position in a particular vertical column the 
nucleolar relations of the ovum of the form specified ; and next 
to the asterisk is placed the name of the authority. In some 
cases two investigators may have reached different conclusions 
in regard to the nucleolar relations, so that for these cases two 
asterisks were employed. 
One must be extremely cautious in any attempt to draw 
conclusions from these data, not only because the data are 
so meager, but also because where data have been culled 
from so many different observers some of the facts may ulti¬ 
mately prove to have been erroneous. Thus many of these 
ova may have been examined at only one point in their develop¬ 
ment, and in others paranucleoli may have been entirely over¬ 
looked, or may have been confused with true nucleoli. But 
taking this mass of observations as it stands, the following gen¬ 
eral conclusions may be drawn: we find that a large number of 
nucleoli is not always characteristic of ova with a considerable 
amount of deutoplasmic substances, for a single nucleolus is 
typical for the birds and for many of the Arthropoda. Further, 
the number of the nucleoli does not seem to be dependent 
upon the amount of yolk, nor upon the mode of cleavage, 
