2 THE JOURNAL OF BOTANY 



sense of Oltmanns,'-^ West,! Chodatj or Wille.§ It may seem 

 undesirable to make a change of this kind, but the facts are 

 perfectly clear and the change must be made. 



The "following can be regarded as well-established species of 

 Protococcits : 



1. P. viridis Agardh, 1824. [= Pleurococcus vulgaris auct. 

 var. ; = Pleurococcus Ncigelii Chodat, 1902.] 



2. P. rufescens Kiitz. [— Pleurococcus rufescens (Kiitz.) 

 Breb.] 



3. P. dissectus Kiitz. l^ Pleurococcus dissectus (Kiitz.) 

 Nag.] 



4. P. Kiltzingii (G. S. West). [== Ple^irococcus Kiltznigii 

 G. S. West in Journ. Bot., xhi, 1904, p. 287, t. 464, f. 9-10.] 



5. P. frigidus (W. & G. S. West). [=^ Pleurococcus frig idus 

 W. & G. S. West in Biol. Keport of Brit. Antarctic Expedit. 

 1907-9, vol. i, part vii, 1911, p. 276, t. 24, f. 40-44.] 



6. P. antarcticus (W. & G. S. West). [== Pleurococcus 

 antarcticus W. & G. S. West, Z.c, p. 276, t. 24, f. 49-51 ; Fritsch 

 in Biol. Report of National Antarctic Expedit. (Scott), vol. vi, 

 p. 13.] 



7. P. fuscatus G. S. West in Fuhrmann & Mayor, Voyage 

 d'exploration scientifique en Colombie. Neuchatel, 1914, p. 1023, 

 t. 21, f. 13. 



The three following are species which are less well established : 



8. P. angulosus Corda. [= Pleurococcus angulosus (Corda) 

 Menegh.] 



9. P. paclvydermus (Lagerh.). [= Pleurococcus ijachydermus 

 Lagerh.] 



10. P. mucosus Kiitz. [= Pleurococcus mucosas (Kiitz.) 

 Eabenh.] 



Many of the other supposed species of Protococcus have been 

 found to belong elsewhere, and the remainder, whether described 

 under that genus or under the generic name of " Pleurococcus," 

 require further investigation. 



XX. — On a New^ Marine Genus of the Volvocace^. 



A sea-water tank used for experimental purposes by the 

 Zoological Department of Birmingham University was noticed 

 in April, 1915, to have developed a deep green colour. The tank 

 \vas kept in the open air on the roof of the building and maintained 

 its intense green colour until the middle of May. The water 

 •contained myriads of a species of Chlamydomonas and of another 

 member of the VolvocaceaB which is not referable to any known 



* F. Oltmanns, Morpliologie und Biologic der Algeii, Jena, 1904. 



t G. S. West, A Treatise on the Britiuli Freshwater Alga, Cambridge, 

 1904. 



+ B. Chodat, J^tiide critique et experimentale sur la Pohjmorphisine des 

 Algues, Geneve, 1909. 



§ N. Wille, " Chlorophyceas und Conjugatse in Engler and Prantl," Die 

 3\atilrUchen Pflanzenfamilien, Nachtrage zu I Teil, Abteilung 2, Leipzig, 1909. 



