108 LIVERPOOL BIOLOGICAL SOCIETY. 
In Ectocarpus pusillus and Giraudia sphacelarioides we have 
possibly a still earlier condition, in which there is appar- 
ently no differentiation between male and female gametes ; 
they conjugate while still both in the swarming condition, 
as is the case in some of the green Confervoidez. In the - 
Cutleriacez (fig. 10), we have a further step in advance. 
The female elements, here known as oospheres, and the 
male elements, now termed antherozoids, are again naked 
biflagellate masses of protoplasm with an orange-red pig- 
ment-spot, but the former are many times larger than the 
latter. These oospheres, or zoospheres as they may not 
inaptly be termed, afford another of the few instances 
known in the vegetable kingdom of undoubted female 
elements endowed with active motion. This, however, 
lasts only for a short time; and it is not until they have 
lost their flagels and come to rest that the antherozoids 
approach them ; and the absorption of a single antherozoid 
into the oosphere is then sufficient to impregnate it. 
Here again it is stated that in Cutleria multifida the oo- 
spheres are capable of germination without being fertilised, 
while the antherozoids have entirely lost this power. 
Zanardinia, which belongs also to the Cutleriacee, pro- 
duces, in addition to these sexual organs, non-sexual 
zoospores in unilocular sporanges; while in Aglaozonia 
reptans these latter are the only kind of reproductive body 
known. In the Dictyotaceze, which are placed by the 
best authorities among Phaeosporex, a further advance is 
established. The flagellate zoospores have disappeared, 
and are replaced by non-motile tetraspores,* as in the 
Floridez ; and the female reproductive bodies are from 
the first motionless non-flagellate masses of protoplasm. 
* Recent observations of Mr. T. Johnson, at present unpublished, appear 
to cast some doubt on this statement. 
