RHODOPHYCEA, OR FLORIDEA 237 
short ooblastema process. When the auxiliary cells 
have been thus fertilised they both divide, and the 
upper portions give rise to the two gonimoblasts of 
the cystocarp, while the lower portions fuse with 
the cells that bear them, and in some cases with the 
thallus-cell from which the fertile shoot originated. 
Fic. 79.—Gloiosiphonia capillaris, fertilisation and development of cystocarp 5 
stages in order of nunibers. 4, auxiliary cell of procarpial branch ; b, basal 
cell; hk, hypogonous cell of carpogonial branch; o00b, ooblastema—in (4) 
protoplast only ; sp, pollinoid ; t, trichogyne. 
With some slight modifications this process is valid 
for the numerous genera and very numerous species 
of Ceramiee. It includes such well-known genera, 
in addition to Callithamnion,* as Lejolisia, Spermo- 
thamnion,*  Sphondylothamnion,*  Ptilothamnion,* 
Grigithsia,* Halurus,* Bornetia,* Monospora,* Pleono- 
sporium,* Haloplegma, Ptilota,* Compsothammion,™ 
