SOME PROBLEMS OF CORLENTERATE ONTOGENY 525 
cell, without the slightest tendency to multiplication. That is 
to say, in species of Hudendrium, Hydractinia, Campanularia, 
Pachycordyle, and others, there is at no time any organ which 
is Ovarian in character, within which masses of primordial ova 
arise and pass through oogonial and oocytie phases familiar in 
other species to be mentioned later; but a given cell of the ento- 
derm which is to give rise to an egg begins to grow, and either 7 
situ or after migration into the gonophore, develops directly into 
a typical egg, and later, after fertilization, gives rise directly to 
an embryo and finally to an individual polyp. On the other 
hand, in many cases, e.g., Pennaria, Tubularia, Syneoryne, Hydra, 
large numbers of primordial ova arise in what may be regarded 
as an ovary where, by a series of cytological changes, they exhibit 
the oogonial and oocytie phases referred to above. These some- 
what strikingly different modes of oogenesis may, for convenience 
be designated as the ‘direct’ or ‘individualized’ and the ‘indirect’ 
or ‘oogonial’ modes. That they are sharply distinet, or quali- 
tatively differentiated types of oogenesis is not claimed. In 
this, as in other phases of development, there are all shades of 
intergradation and relation to be found in these and other species 
of Cnidaria. 
Correlated with these apparently widely divergent modes of 
origin are those of nutrition and growth. In the ‘direct’ or 
‘individual’ ova nutrition is almost invariably likewise through 
the direct medium of the adjacent tissue cells, which supply by 
diffusion the appropriate nutritive plasma. On the other hand, 
in Ovarian eggs, which involve oogonial and oocytie generations, 
there arise indefinite masses of primordial ova; and the growth 
of certain of these as ovarian eggs, Is largely through the active 
appropriation of the excess primordial ova, which are literally 
devoured whole, or predigested to a liquid plasma, which is then 
absorbed. Illustrations of both these processes are too familiar 
to call for special emphasis. While the two processes of nutri- 
tion are thus apparently different, intermediate cases are not 
unknown, e.g., Eudendrium hargitti, recently described by Cong- 
don (’06, p. 39) has been found to comprise something of both 
modes. And, though it belongs to a genus in which oogenesis 
JOURNAL OF MORPHOLOGY, VOL. 22, No. 3 
