1901] EREMOSPHAERA AND EXCENTROSPHAERA 323 
This work was commenced in the Cryptogamic Laboratory 
of Harvard University, and my sincere thanks are due to Dr. 
Farlow and to Dr. Thaxter for their helpful criticism of the 
investigation carried on while there. 
DARTMOUTH ini 
Hanover, N. H. 
BIBLIOGRAPHY. 
1. CHODAT, R., Ueber die Entwickelung der Evemosphaera viridis DeBy. 
Bot. Zeit. 53: 137-148. 1895. 
2. DE Bary, A., Untersuchungen iiber die Familie der Conjugaten. 
Leipzig, 1858. 
3. DE Tonl, J. B., Sylloge Algarum 1 :616. 1889. 
4. De WILDEMAN, E., Comptes rendus de la Soc. Roy. de Bot. Belge. 
1894. 
5. HENFREY, A., On Chlorosphaera. Trans. Micr. Soc. Lond. 7: 25-29. 
1859. 
6. HormeisTER, W. F. B., Ueber die Fortpflanzung der Desmidieen und 
Diatomeen. Leipzig. 1857. 
7. WILLE, N., Die natiirlichen Pflanzenfamilien, Algen 17:58. 1897. 
8. WOLLE, F., Freshwater algae of the United States. 1: 201. 1887. 
EXPLANATION OF PLATES. 
All the figures are from ink drawings sketched in with an Abbé 
camera. In the reproduction = are reduced about one fourth. Figures 
44-78 are drawn with a Leitz +5 z (oil), oc. 3; all the others with a Leitz } oc. 3. 
The magnifications given are ihe original ones before reduction and allow for 
projection. 
PLATE X, Eremosphaera viridis De Bary. 
Fie. 1. Surface view of large variety (Ridge hill material). x 250. 
Fig. 2. Section of same showing nucleus and protoplasmic strands. 
X 250. 
Fig. 3. Surface view of small variety (Naushon material). X 250. 
Fic. 4. Surface view showing the retreat of the chromatophores under 
the influence of strong sunlight. X 250. 
Fig. 5. So-called “rejuvenescence.” x 250. 
Fic. 6. Beginning of the division into two. 
FiG. 7. Division completed and liberation of auughter cells. X 250. 
Fic. 8. Division of mother cell into four. x 250 
FIG. 9. Division completed and liberation of daughter cells. x 250. 
Fic. 10. Escape of cell from old wall after “rejuvenescence.”” X 250. 
