nu 
Some Observations on the Chromosome Vesicles in the Maturation etc. 101 
compact, one vesicle forms but when it becomes scattered, several 
may appear. 
The sperm nucleus in Fig. 18, presents one structure, the 
meaning of which is not elear. In this seetion of the nucleus there 
are three sharply defined masses of chromatin, one of which is free 
from any connection with linin fibres.. The other two are surrounded 
by a substance that takes a distinet plasma stain and the edge of 
which is continuous with the linin fibres. It looks as if there were 
here an extra amount of substance similar to linin and from which 
linin arose concentrated about these two chromatic masses. To 
summarise we may say that vesieles similar in appearance and con- 
tent are found during the prophase stage of the second maturation; 
in the polar cells; and in connection with the male and female pro- 
nuclei. 
In addition to the usual maturation phenomena in these Nudi- 
branchs, a portion of the cell contents may be budded off without 
the mitotie or amitotic process. Just after the eggs are deposited 
or even while the animal is laying, the eggs may, while changing 
from an irregular to a spherical form, give off a large part of the 
cell, a fourth or fifth of the whole cell is thus given off. The for- 
mation of these small cell like bodies was observed in many spawn 
masses of these Nudibranchs. They appear before the first polar 
cell has had time to be formed. While observations were being 
made on the living eggs, these large bodies were thought to be 
simply unusually large polar cells. 
In a study of the sections of M. Gouldü I was fortunate in 
securing two spawn-masses in which a number of the eggs were 
undergoing the formation of these peculiar bodies. Fig. 23 is a 
drawing made from two adjacent sections showing this cell-like body 
still attached to the egg and the first maturation figure in the pro- 
phase stage. The position of each is such that there can be no 
possible connection between them. The budded cell-like body is 
full of deutoplasmie spheres, and a few cytoplasmie granules are 
evident. But there is no evidence of a nucleus or of free chromo- 
somes either in this body or the cell proper apart from the maturation 
figure. An examination of all of the sections of this egg with a 
Zeiss homog. aprochromatie 2 mm lens and compensating oculars 
as well as with tbe 1/12 oil immersion lens failed to reveal any 
structure which might be designated as a nucleus or chromosome or 
ehromatie substance in connection with the formation of this cell-Iike 
