RHODOPHYCEA, OR FLORIDEA 205 
there are formed carpospore-bearing fruits; or the 
carpogonium conjugates with an auxiliary cell by 
means of a long or short (generally short) ooblastema 
filament, and the auxiliary cell then gives rise to the 
carpospore-bearing fruits. This remarkable and 
unique power of handing on the fertilising influence 
from the carpogonium which receives it to other 
(auxiliary) cells, which then behave like fertilised 
cells, is of great interest, since it appears to be with- 
out a parallel in nature. The filaments, gonimoblasts, 
which bear the carpospores always spring from 
fertilised cells, and the carpospore fruits may be either 
borne free or within special capsules, or immersed 
within the thallus, according to the group. 
Non-sexual reproduction is effected by motionless 
spores called detraspores, from their usual occurrence 
in fours within a sporangium. However, one only or 
two are formed in some cases ; and the arrangement 
of the fours is a variable one. When all four spores 
are formed simultaneously they present together the 
form ofa tetrad (Fig. 61, «@); but when they are formed 
by successive bipartitions, two different types arise. 
Tf in the second division the walls are parallel to the 
first one formed, the result is a series of four spores, one 
above the other, called zonate tetraspores (Fig. 61, ¢). 
If the two secondary walls are not parallel, but 
perpendicular to the first formed, and not in one 
plane with each other, but at an angle of 90°, the 
result is the arrangement called cruciate tetraspores 
(Fig. 61, 0). The tetraspores occur externally, and 
also within the cortical layers of the thallus. In 
some cases they occur in large numbers on definite 
