220 SEAWEEDS 
closely allied genus Colacolepis is epiphytic on Phyl- 
lophora nervosa and Ph. rubens. It forms a small 
crust-like growth on the surface of its host, and is 
closely attached to its epidermal layer. It also is 
reproduced only by its tetraspores, so far as is 
known. 
The family of Rhodophyllidee is distinguished by 
Fic. 68.—Eucheuma spinosum reduced. 
the gonimoblast being divided into a number of 
gonimolobes which radiate from the auxiliary cell in 
all directions. These gonimolobes stretch out separ- 
ately into the surrounding tissue of the thallus and 
their terminal cells, or in other cases the upper cells 
as well, form the carpospores. The auxiliary cell is 
frequently very large, and it forms the central cell of 
the whole fruit body. 
There are only four British genera of this family, 
