166 BROOKLYN BOTANIC GARDEN MEMOIRS 
Klein, L. Morphologische und biologische Studien ueber die Gattung Volvox. 
Pringsh. Jahrb. 20: 133. 1889. 
Klein, L. Neue Beitrage zur Kenntnis der Gattung Volvox. Ber. d. d. bot. Ges. 
VeRA2»  losg: 
Overton, E. Beitrag zur Kenntnis der Gattung Volvox. Bot. Centralbl. 39: 65. 
1889. 
Klein, L. Vergl. Untersuchungen ueber Morphologie und Biologie der Fortpflanzung 
bei der Gattung Volvox. Ber. d. naturf. Ges. zu Freiburg i. B. 5: 1890. 
Meyer, Arthur. Ueber den Bau von Volvox aureus Ehrb. und V. globator Ehrb. 
Bot. Centralbl. 63: 225. 1895. 
Swingle, W. T. Zur Kenntnis der Kern- u. Zellteilung bei den Sphacilariaceen. 
Prings. Jahrb. 30: 299. 1895. 
Kofoid, L. A. Plankton Studies. II. On Pleodorina illinoisensis, a New Species 
from the Plankton of the Illinois River. Bull. Il. State Lab. Nat. Hist. 
Ro 27g 1tskoys- 
R. Chodat. Algues vertes de la Suisse. Berne. 1902. 
Oltmanns. Morphologie u. Biologie der Algen, Jena, 1904. 
Harper, R. A. The Structure and Development of the Colony in Gonium. Trans. 
Am: Mic.)So0e! 31: 1655 1912. 
Janet, C. Le Volvox. Limoges, 1912. 
Magnus, W. Ueber zellenférmige Selbst-differenzierungen aus flussiger Materie. 
Ber. d. d. bot. Ges. 31: 290. 1913. 
Harper, R. A. On the nature of types in Pediastrum. Mem. N. Y. Bot. Gard. 6: 
Olay LOLG: 
DESCRIPTION OF PLATE II 
All figures of asexual reproduction in Volvox taken with Zeiss apochrom, ob- 
jectives and the compensating eye-pieces. 
Fic. 1. Two-celled stage of young colony. X about 600. 
Fic. 2. Second division just completed. XX about 600. 
Fic. 3. Four-celled stage of young colony. X about 350. 
Fic. 4. Four-cell stage, one cell elongating preparatory to third division. 
< about 350. 
Fic. 5. Ejight-cell stage showing the wheel or radial arrangement of the cells. 
x about 350. 
Fic. 6. Samestageaslast. The young colony photographed after being teased 
out of the mother cell. X about 400. 
Fic. 7. Young colony not yet set free from mother colony and cell walls not 
yet gelatinized.. X about 400. 
