
98 - LIVERPOOL BIOLOGICAL SOCIHTY. 
require to be protected during the winter. It would be 
running a needless risk to produce motile embryos at the 
beginning of winter; hence the daughter-embryos remain 
enclosed within their protecting cell-walls and in the 
protective capsule formed round them by the mother 
plant until the followimg spring, when they emerge as 
flagellate embryos, ready to seek a resting place and 
develope into sporophytes. 
Perfectly similar cases are found among the Rhodo- 
phycee, in fact the production of a number of embryos as 
the result of one impregnation is a characteristic feature of- 
that group, although many modifications in the mode of 
production of these is exhibited by different members of 
the group. So too in many Fungi the “ascospores” and 
‘“‘carpospores”’ are simply products of embryonic fission, 
or, in some cases of embryonic gemmation, i.e. embryos, 
and in no sense spores, which are never produced as the 
result of sexual union. 
When special cells are set apart for the production of 
new individuals it is an obvious economy to the organism 
to produce many embryos as the result of one impreg- 
nation, in addition to the multiplication of the chances of 
its remaining on the surface of the earth. Hmbryonic 
fission in fact occurs most markedly in those groups where 
we would expect it, i.e. where the sexual reproductive 
process is a complicated and elaborate one, and where 
there is a possible chance of extinction if a sufficiency 
of embryos be not produced, and margin allowed for 
loss. Hence the parasitic Fungi, and more especially the 
Ascomycetes, exhibit this peculiarity to a very marked 
degree. In other forms, such as Mdogonium extra pro- 
vision is made for logs of embryos; in Coleocheta and 
the Rhodophycez we have to consider as well the time of 
year at which the embryos are produced and the necessity 


