PORIFERA, CQELENTERATA, VERTEBRATA 97 
views. He finds that “The egg cells of Campanularia 
flexuosa arise in the entoderm of the pedicel of the 
gonophore, by the transformation of a single 
epithelial cell, or from the basal half of a divided 
cell, the distal half of which remains an epithelial 
cell and retains its epithelial functions. Therefore 
the egg cells have come from differentiated body- 
cells (so-called) and there is no differentiation of 
the germ-plasm in the sense that germ-cells are 
early differentiated and set aside and do not partici- 
pate in the body functions. Any cell of the ento- 
derm of Campanularia fleruosa may become an egg 
cell if it is in the position of the developing gono- 
phore”’ (p. 411). 
In spite of these attacks upon the germ-plasm 
theory as applied to ccelenterates, the possibility 
and even probability of such a condition seems to 
the writer to exist, and he is inclined to accept 
Downing’s position in the matter. Weismann’s 
views must, however, be modified, since the germ 
cells are not ectoderm cells, as he claims, nor do 
they belong to any germ layer. They are, according 
to the view adopted here, set aside as a separate 
class of cells at some stage during early development, 
are scattered about among the cells of the ectoderm 
or entoderm, depending upon the species, or lie in 
the mesoglea. We know that external conditions 
may stimulate reproductive activity in certain 
coelenterates (Frischholz, 1909) and consequently 
the development of germ cells, and we must conclude 
that these germ cells are present at all times in a 
H 
