86 GERM-CELL CYCLE IN ANIMALS 
garding the germ cells in the following genera is 
considered below: (1) Eudendrium, (2) Hydractinia, 
(3) Pennaria, and (4) Clava. 
EvupEnpRium. Five species of this genus have 
been investigated. In E. racemosum, according to 
Weismann (1883), the ova arise in the ectoderm and 
the male germ cells originate either from entoderm 
cells or from ectoderm cells that later migrate into the 
entoderm. Ischikawa (1887) asserts that the germ 
cells arise in the ectoderm and migrate into the en- 
toderm, and Hargitt (1904a) found ova in both 
the ectoderm and entoderm, but, since those in the 
entoderm were always the smaller, he concludes that 
they may have wandered into that layer from the 
ectoderm, though such a migration was not ob- 
served. 
In E. capillare Hargitt found ova in the entoderm 
except in one case where they occurred in the ecto- 
derm. This author also reports the female germ 
cells of E. tenue and E. racemosum from the entoderm 
only. The ova of the EupDENDRIDz when first dis- 
tinguishable “are slightly larger than the ordinary 
cells of the surrounding tissue, and differ also in 
shape, being generally ovoid or spherical and with 
comparatively conspicuous nuclei. . . . Growth at 
this period would seem to take place in situ, through 
the direct nutritive activity of the surrounding tissue 
cells... . As growth continues, the ova become 
more or less amceboid, migrating toward the gono- 
phore region, where they seem to aggregate in con- 
siderable numbers, the presence of which may act as a 
