186 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Filaments without a gelatinous sheath, spores next to the hetero- 

 cysts . Sphwrozyga. 



12. Filaments with a gelatinous sheath 15 



Filaments without a gelatinous sheath 13 



13. Filaments spirally twisted Spirulina. 



Filaments not spirally twisted 14 



14. Cells bluish or purplish green .... Oscillaria. 



Cells colorless or containing opaque granules Beggiatoa. 



15. Filaments free Lyngbya. 



Filaments adherent in meshes Symploca. 



Filaments united in bundles and. surrounded by a general gelatinous 



sheath . . Microcoleus. 



16. Filaments free Calothrix. 



Filaments imbedded in a dense mass of jelly 17 



17. Filaments nearly parallel, fronds forming a thin expansion.. .Isactis. 

 Filaments diverging from the base of the hemispherical or somewhat 



flattened fronds Bivularia. 



Filaments simple at the surface and forking in the interior of the 

 vesicular fronds Hormactis. 



18. Fronds unicellular 19 



Fronds multicellular 20 



19. Cells small, ovoidal, prolonged into a long, root-like process at the 



base Codiolum. 



Cells large, filamentous, pinnately branching Bryopsis. 



Cells large, with few, erect, alternate branches, some of which swell 



at the end and bear numerous spores Berbesia. 



Cells very long, cylindrical, with irregular or subdichotomous 



branches, spores large", solitary, in special lateral or terminal cells. 



*Vaucheria. 



20. Fronds membranaceous ■ , 21 



Fronds filamentous 22 



21. Fronds formed of a single layer of cells Monostroma. 



Fronds composed of two layers of cells, which in some cases sepa- 

 rate so as to form tubular fronds Ulva. 



22. Filaments simple 23 



Filaments branching 24 



23. Small algse, filaments soft and flaccid Ulothrix. 



Bather coarse algse, filaments more or less rigid, often twisted to- 

 gether Chcetomorpha. 



24. Some of the cells bearing long, hyaline hairs Bulbocoleon. 



Hairs wanting _, 25 



25 Branches small and root-like Bhizoclonium. 



Branches distinct Cladophora. 



26. Fronds irregularly globose, hollow, gelatinous . Leathesia. 



Fronds forming crusts or expanded pellicles 27 





