GERM CELLS IN NEMATODES, SAGITTA 185 
In the eggs of Myzostoma, Wheeler (1897) found 
that the nucleolus of the germinal vesicle does not 
dissolve soon after it is cast out into the cytoplasm 
during the formation of the first maturation spindle, 
but remains visible at least until the eight-cell stage, 
at which time it lies in the large posterior macromere, 
a cell which “‘ very probably gives rise to the entoderm 
of the embryo.” Later embryonic stages were not 
studied. According to Wheeler ‘“‘the nucleoli are 
relegated to the entoderm cells as the place where 
they would be least liable to interfere in the further 
course of development and where they may perhaps 
be utilized as food material after their disintegra- 
tion” (p. 49). 
McClendon (19066) has likewise described a body 
embedded in the cytoplasm of the egg of Myzostoma 
clarki which he derives from the “accessory cells” 
which, as Wheeler (1896) has shown, attach them- 
selves to either pole of the odcytes. These ‘“acces- 
sory” cells are really the ‘“‘Néhrzellen” of other 
authors. The cleavage of the egg was not studied. 
Buchner (19100) suggests that this body described 
by McClendon and the “‘nucleolus” of Wheeler are 
identical and that through them the keimbahn may 
be determined. 
Granules of various sorts have been noted in the 
eggs of various animals which are segregated in par- 
ticular blastomeres and may have some relation to 
the keimbahn. For example, among the mollusks, 
Blockmann (1881) has described the appearance of 
a group of granules in the early cleavage cells of 
