124 SEAWEEDS 



The erect, green, assimilating shoots are, as has 

 been indicated, very variously branched, and the 

 species are classified mainly on the characters so 

 displayed. They root in fine sand or mud, and 

 commonly possess a creeping surculus or rhizome 

 which gives off roots below and erect foliar shoots 

 at intervals after the fashion of higher plants. The 

 network of trabeculaB or cross-beams is very dense 

 in most species, and traverses the cell-contents in all 

 directions. They spring from the substance of the 

 outer wall-membrane (Fig. 32, c and d), and their 

 principal function appears to be that of imparting 

 support to the walls, though other functions have 

 been speculatively ascribed to them without much 

 show of reason. 



Dr. Correns has recently made a minute study l of 

 the membrane, and has found that after treatment 

 with sulphuric acid it has exhibited the formation of 

 numerous sphasrocrystals, showing differences from 

 those of cellulose demonstrated by Gilson and 

 Blitschli. From the tests he has imposed, he has 

 come to the conclusion that the membrane of Cauforpa 

 does not consist of cellulose in the narrow sense, but 

 of a substance not yet fully known, and different 

 from callus, fungus-cellulose, reserve-cellulose, etc. 

 He has obtained similar results from two species of 

 Bryopsis, and is inclined from this to regard with 

 favour the view, otherwise vaguely indicated, of a 

 relationship of this singular genus with Bryopsis. 



So little indication is there, however, of relation- 

 ship with other Alga3, that we have but the one fact 

 1 Ber. Deutsch. Bot. Gesdlsch., 1894, bd. xii., p. 355. 



