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. 



7: 42. 1889. 

 Overton, E. Beitrag zur Kenntnis der Gattung Volvox. Bot. Centralbl. 39: 65. 



1889. 

 Klein, L. Vergl. Untersuchungen ueber Morphologic 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. 111. State Lab. Nat. Hist. 



5: 2^l. 1898. 

 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. Soc. 31: 65. 1912. 

 Janet, C. Le Volvox. Limoges, 19 12. 

 Magnus, W. Ueber zellenformige Selbst-difTerenzierungen 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: 



91. 1916. 



DESCRIPTION OF PLATE II 



All figures of asexual reproduction in Volvox taken with Zeiss apochrom, ob- 

 jectives and the compensating eye-pieces. 



Fig. I. Two-celled stage of young colony. X about 600. 



Fig. 2. Second division just completed. X about 600. 



Fig. 3. Four-celled stage of young colony. X about 350. 



Fig. 4. Four-cell stage, one cell elongating preparatory to third division. 

 X about 350. 



Fig. 5. Eight-cell stage showing the wheel or radial arrangement of the cells. 

 X about 350. 



Fig. 6. Same stage as last. The young colony photographed after being teased 

 out of the mother cell. X about 400. 



Fig. 7. Young colony not yet set free from mother colony and cell walls not 

 yet gelatinized. X about 400. 



