SUB-CLASS I 
PHHOPHYCEAZ 
WITH the exception of some of the species of 
Lithoderma and the genus Plewrocladia, represented 
only by a minute form of doubtful affinity dis- 
covered by Alexander Braun in the Tegeler See 
near Berlin, all the Phwophycew, or Melanophycee as 
they are otherwise called, are seaweeds. They 
agree in the fact that all their motile reproductive 
cells, zoospores, antherozoids, and gametes are pro- 
vided with two lateral cilia, one pointed forwards 
and the other backwards in motion; in the fertilisa- 
tion of their oospheres and the conjugation of gametes 
outside the parent plant, and the direct germination 
of the zygote which is the product of this union; 
in the possession of brown chromatophores tinged 
with phycophwine and phycoxanthine (the phyco- 
pheeine being soluble in water and the phyco- 
xanthine in alcohol, the compound pigment being 
termed pheeophyll) ; and in having mostly but one 
nucleus in the vegetative cells. The vegetative 
body of the plants coming under this sub-class is 
of great diversity, including the most highly 
organised of all seaweeds, of giant dimensions and 
