260 GROWTH AND ORIGIN OF MULTICELLULAR PLANTS. 
that, contrary to the general statement, a gelatinous outer sheath 
i ria, an e material of which it is co d 
is most complete, and of the two media air is most potent in pro- 
ducing this effect; a statement which applies equally to Phanero- 
oi : : 
gr r 
filaments break up, each portion secreting an excess of mucilage, 
becomes softened. and by cell-division a filament is formed. 
in marine Alge, that range in distribution from high-tide level 
apparent. Fucus vesiculosus L., when growing in places which are 
; ae é Pp 
antheridia and oogonia. As this species is followed down to low- 
tee a gradual inerease in size is observable, in the last-mentioned 
of the peculiarities manifested by the protoplasm is its power 0 
primordial or naked cells, whether animal or vegetable, - 
