508 CHARLES W. HARGITT 
etc. They were described in some detail and various suggestions 
and comparisons submitted as to their significance. 
In the eggs of Hydractinia very similar structures were encoun- 
tered, though less conspicuous and less constant than in Pennaria. 
Certain of these are shown in figs. 14 to 22. As to their signifi- 
cance or function I have nothing new to offer beyond that pre- 
viously suggested. Their more obvious function would seem 
the two-fold one of connecting adjacent blastomeres, and afford- 
ing codrdinating bonds for the entire egg during development. 
These suggestions could hardly apply to the papillose structures 
of the surface, and their presence must be regarded as problemat- 
ical. 
3. The early embryo, morula. With the progress of cleavage 
toward completion the irregularities of surface, due to ectosarcal 
structures above mentioned and erratic cleavage, which were so 
conspicuous a feature, gradually disappear and the embryo tends 
to become more or less typically spherical and blastula-like. But 
in comparatively few Hydrozoa does a typical blastula occur. 
In my earlier accounts of the development of Eudendrium and 
Pennaria attention was directed to the presence of a true morula 
as the embryonic stage resulting from cleavage, and also to the 
entire absence of a stage comparable to a coeloblastula. This is 
likewise the condition to be found in Hydractinia and Clava. 
Rittenhouse (’07) has shown the same to be the case in Turri- 
topsis nutricula. It will be shown in a later connection that this 
is the dominant type of cleavage embryo throughout the entire 
phylum. At no time is there to be found in either Hydractinia 
or Clava a distinctive or permanent cleavage cavity, though there 
may often be found certain intercellular spaces which are desig- 
nated as such, but the correctness of which may be seriously 
challenged. This, again, will be considered in more detail in a 
later section. 
For some time following the apparent completion of cleavage 
and the establishment of the morula there seems to be a period 
of quiescence. This is such, however, only in appearance; for 
in reality there exists a condition of active cell proliferation, as 
may easily be demonstrated by means of sections of embryos at 
this time. This has been especially demonstrated and emphasized 
