437 
§ 20. BYSsoiDEiE, Ag. Draparnaldia, Bory. 
Byssocladium, Ag. Draparnaldiella, 
Byssocladiella, Gaill. Gaill. 
Alysphaeria, Turp. Myxonema, Fries. 
Mycinema, Ag. Chcetophora, Ag. 
Amphiconium, Nees. Chcetophorella, Gaill. 
Chroolepus, Ag. Corynephora, Ag. 
Trentepohlia, Ag. Myrioneraa, Grev. 
Protonema, Ag. § .22. Rivularie^, 
Hygrocrocis, Ag. Harv. 
Chamoenema, Kutz. ? Rivularia, Roth. 
Leptomitus, Ag. Linkia, Michel. 
Pythium, Nees. Linkiella, Gaill. 
Achlya, Nees. [Anhaltia, Schwabe.] 
Pusillina, Bory. § 23. Nostochine^e, 
§ 21. Batrachosper- Ag. 
MEiE, Ag. Cryptococcus, Kutz. 
Mesogloia, Ag. Micraloa, Biasol. 
Helminthora, Fries. [Sphcerothromhium, 
.^gira, Fries. Kutz.] 
Batrachospermum, Protococcus, Ag. 
Roth. Haematococcus, Ag. 
Charospermum, l.k. Microcystis, Kutz. 
Palmella, Lyngb. 
Coccochloris, Spr. 
Stereococcus, Kutz. 
Hydrococcus, Kutz. 
Echinella, Ach. 
Nematococcus, Kutz. 
Nostoc, Vauch; 
Nostochium, Lk. 
Nostocella, Gaill. 
Hydrocoryne, Schwab. 
Mppendix. 
Scythymenia, Ag. 
Inoderma, Kutz. 
§ 24. DESMiDiEiE,Grev, 
Meloseira, Ag. 
Gaillonella, Bory. 
Leda, Bory ? 
Lysigonium, Lk. 
Desmidium, Ag. 
§ 25. Fragillarie^, 
Ag. 
Fragillaria, Lyngb. 
Nematoplata, Bory. 
Achnanthes, Bory. 
Achnantella, Gaill. 
Diatoma, Ag. 
Candollella, (ex 
parte) Gaill. 
Frustulia, Ag. 
§ 26. Styllarie^, Ag. 
Styllaria, Ag. 
Licmophora, Ag. 
Meridion, Ag. 
Lunulina, (ex parte) 
Bory. 
§ 27. Cymbelle^, Ag. 
Gomphonema, Ag. 
, Hydrurus, Ag. 
Cluzella, Bory. 
Gloiodictyon, Ag. 
Homaeocladia, Ag. 
Berkeleya, Grev. 
Micromega, Ag. 
Schizonema, Ag. 
Monema, Grev. 
Spermogonia, Bonn. 
Girodella, Gaill. 
Cymbella, Ag. 
Nacicula, Boiy ? 
Bacillaria, (ex parte) 
Nitsch. 
In the 14th vol. of JVov. Act. Acad. Cccs. Leap. Cur. are four new genera of 
I minute Algae, proposed by Dr. F. I. F. Meyen : — Pediastrum, Scenedesmus, 
Sphaerastrum and Staurastrum. They are so obscure that I cannot decide 
upon their affinities, and the author himself dechnes to assign them a place in 
the system. R. K. Grev. 
In order to complete the foregoing list of genera as far as is in my power, 
I have added the following names, which I do not find in Dr. Greville’s letter. 
Sphaerotilus, Kutz. Isthmia, Ag. Closterium, Nitzsch. Biddulphia, Gray. 
Ulothrix, Kutz. Encyonema, Kutz. Heterocarpella, Turp. Geminella, Turp. 
Exilaria, Grev. Trochiscia, Kutz. Micrasterias, Ag. Glcioneraa, Ag. 
Aristella, Kutz. 
