204 SEAWEEDS 
may be straight (Fig. 62,b) or have a spiral twist or 
two. The carpogonium is situated at the end of a row 
of usually three or four cells, the carpogonial branch, 
and the cells of this row immediately adjoining it 
acquire as a rule special characters. This carpo- 
gonial branch may be either superficial or within the 
body of the thallus. Fertilisation takes place by a 
pollinoid becoming attached to the apex of the pro- 
jecting trichogyne (Fig. 62, c), and the cell-wall having 
been resorbed at the point of contact, the contents of 
pollinoid and trichogyne become united. The nucleus 
of the pollinoid disappears, and though its fusion with 
that of the carpogonium has not been observed, it 
may be inferred from analogous cases that it travels 
down the trichogyne to the carpogonial nucleus, and 
unites with it. The cell-wall then thickens at the 
base of the trichogyne and closes the communication ; 
and the trichogyne slowly withers. 
The farther development of the fertilised carpo- 
gonium is very various, but it is to be noted that, 
unlike the homologous bodies in other Algz, it does 
not separate itself from its tissue connections, and 
its original cell-wall remains as its own proper 
membrane. Its farther development follows certain 
typical plans characteristic of the groups of Rhodo- 
phycee, and, while these are described in detail in the 
proper place, they may be briefly stated as follows. 
The carpogonium itself may in the simplest case give 
rise to a tuft of carpospore-bearing filaments; or 
there grow forth from it several simple or branched 
ooblastema filaments which conjugate with other cells, 
auxiliary cells, and as a result of this conjugation 
