15 



formation of the cell contents I have not found. In Microdic- 

 tyon the apices of the branches fix themselves to neighbour- 

 cells and in order to strengthen the attachment a rather thick 

 cellulose ring is formed at the top of the branches, in Anadyo- 

 mene, where the cells grow quite closely together along all their 

 sides, such a thickening is also found at the summit of the cells. 



To the Valonieae I refer Valonia and Dictyosphseria. In 

 regard to their cell division they are certainly rather different, 

 the cells in Valonia as is well known being divided by lentiform 

 walls, while in Dictyosphseria the cells are divided by segrega- 

 tive cell-division. But on the other hand the two forms show 

 considerable agreement. Dictyosphseria has for example nume- 

 rous small lentiform cells from which the hapters grow out and 

 in some species of Valonia the cell contents often are divided 

 into balls. 



This group also agrees fairly well with that of Wille, Blasto- 

 physa I refer to the Chaetophoraceae and Apjohnia I should prefer 

 to place near Striivea, Chanisedoris etc. 



In the third Subfamily Boodleas I place Boodlea and Clado- 

 phoropsis. Both these forms have irregularly ramified filaments 

 forming jEgagropila-\ike clumps. The division of cells takes 

 place by the segregative cell-division. Unicellular tenacula 

 occurring in the summit of the branches (Boodlea), or every- 

 where at the side of the filaments (Cladophoropsis) contribute 

 to fix the filaments together. 



Finally, the Subfamily Siphonocladeae comprises Striwea, 

 Chamasdoris, S iphonocladiis and Ernodesmis. Common to all 

 is that the primary, cylindric cell persists as stipes, which by 

 means of rhizoids is fastened to the substratum and in the nether- 

 most part (in Chamaedoris the whole stipes) is provided with 

 annular constrictions (except in Striwea anastomosans which 

 on the whole is a connecting link to Boodlea). The cell division 

 is performed by segretative cell-division except in Ernodesmis, 

 where, so far I have been able to see in my material, it is accom- 

 plished nearly as in Valonia, but ball-formation of the cell con- 

 tents is rather common in this form also. 



Common to all the four subfamilies of the Valoniacese is 

 the shape of the chromatophores and the cell contents upon 

 the whole. The chromatophores consist of numerous small poly- 

 gonal bodies; in the young cell they are reticularly connected 

 forming in this way a parietal net work, in the older part of the 

 thallus they are most often separated. How far it is possible 



