248 SEAWEEDS 
pollineid pass into and unite with those of the female 
cell. There is no development of gonimoblast, but 
the whole of this fertilised cell becomes a spore and 
emerges from its membrane, or it first divides once or 
twice and forms several spores. The whole of this pro- 
cess may represent a very much reduced or an ancestral 
Rhodophycean type, but there is a great gulf between 
it and the simplest form of indubitable Red Seaweed. 
The non-sexual spores, the so-called tetraspores, of 
Bangiacee leave us also in doubt. The whole of the 
contents of a single thallus cell go to the formation 
of one of the spores which are unciliated, at first 
without a membrane, but afterwards with one. In 
some cases there is a preliminary division (once or 
twice) of the thallus cell. It may be recalled that 
monospores (the undivided tetrasporangium) occur 
in certain Rhodophycee, but even then there is no 
conclusive evidence here for or against, though it 
leans towards inclusion. On the whole, and con- 
sidering the difficulty of placing them elsewhere, the 
Bangiacee may be lett beside the Rhodophycce, though 
not within the group. 
The Geographical Distribution is world wide. It is 
however a small order with comparatively few species, 
though these are of very variable character. Bangia, 
Goniotrichum, Erythrotrichia, Porphyra, and Diplo- 
derma, are all British, and most of them abundant on 
our shores. The species of Porphyra furnish the 
edible Laver. 
