332 Phillips on a Comparative Study of the 



96. Zopf. — "Zur Morphologic der Spaltpflanzen." Leipzig, 1883. 



97. Zopf. — "Weitere Stiitzen fiir meine Theorie von der Inconstanz der 



Spaltalgen Tolypothrix amphihica, Zopf." Ber. d. deut. bot 

 Gesell., Bd. i, 1883. 



98. Zukal. — "Beitrage zur Kenntniss der Cyanophyceen." Oesterr. bot. 



Zeitschr., 1894. (Also reviewed in Bot. Cent, for 1895.) 



99. Zukal. — "Ueber den Zellinhalt der Schizophyten." Sitzungsberichtc 



der K.-Akad. d. Wiss. in Wien, Bd. ci, 1892. 



100. Zukal. — "Ueber den Zellinhalt der Schizophyten." Ber. d. deut. 



bot. Gesell., Bd. x, 1892. 

 loi. Zukal. — "Neue Beobachtungen ueber einige Cyanophyceen." Ber. 

 d. deut. bot. Gesell., Bd. xii, 1894. 



102. Zukal. — "Zur Frage ueber den Zellinhalt der Cyanophyceen." Ber. 



d. deut. bot. Gesell., Bd. xii, 1894. 



103. Zukal. — "Beitrage zur Kenntniss der Cyanophyceen." Oesterr. bot. 



Zeitschr., 1894. 



(n) EXPLANATION OF PLATES. 



Plate XXIIL 



Fig. I. Cell of Oscillaria shovi^ing the chromatin vesicles of the central 



body in the resting condition. Also shows the cilia on each side 



wall. 

 Fig. 2. Diffuse net-spireme stage of division in Oscillaria. 

 Fig. 3. Net-spireme drawn to the equator of the cell of Oscillaria. 

 Fig. 4. Net-spireme constricting and division walls of consolidating 



microsomata growing inward from the side walls. 

 Fig. 5. Division of cell of Oscillaria completed. 



Fig. 6. Cell of Oscillaria with diffused nucleus, from which the net- 

 spireme of Fig. 2 will form. 

 Fig. 7. Cell of Oscillaria showing the beginning of the collar-like 



ingrowth, which will form the division wall. Ingrowth composed 



of microsomata of cellulose. 

 Fig. 8. Spireme forming into segments or chromosomes in Oscillaria. 

 Fig. 9. Same as Fig. 8, but with chromosomes and spindle fully 



formed. 

 Fig. 10. Same as Fig. 9, but with the chromosomes dividing. 

 Fig. II. Cell of Oscillaria in which two large chromosomes have 



formed. 

 Fig. 12. Same as Fig. 10, but with heavier chromosomes. 

 Fig. 13. Chromosomes shown in Fig. 11 are here shown dividing. 

 Fig. 14. Division completed. 



Figs. 15-20. Successive division stages in O. Froehlichii. 

 Fig. 21. Spireme of Oscillaria much enlarged. 



