DE. JULIUS SCHAARSCHMIDT ON AFGHANISTAN ALGJ1. 243 



filaments of this Anabcena (Cylindrospermum) are composed of 

 cylindrical or more or less globular cells. The spores are much 

 larger than the ordinary cells, from which on their first appear- 

 ance they are not readily distinguishable (Plate V. fig. 3a); but 

 when the frond has attained a certain age, the spore-cells begin 

 to enlarge, and finally assume a form and size apparently fixed ; 

 the matured spores are cylindrical, rounded at the ends, and sur- 

 rounded with distinct yellowish coats. The relative position of 

 spores and heterocysts is various. The contents of the hetero- 

 cyst is paler, the colour of the cell- wall yellowish. The filaments 

 are seen in division in Plate V. fig. 2. The cell at first seems 

 merely to elongate until it obtains nearly twice its original 

 length, when the division commences. A median constriction 

 divides the cells into two daughter cells, the filaments then assu- 

 ming a moniliform aspect. The cells are closely connected, no 

 nuclei being discernible as in the JVbctoe-ceUs*. By this process 

 the filament rapidly increases in length ; but at the ends the new 

 joints become further separated until they are almost detached 

 (Plate V. fig. 7 a). The separated cells remain together and form 

 irregular masses (Plate V. fig. 8) resembling Syneclococcus. These 

 changes were observed from dried material, but were traced from 

 uninjured filaments, and remind us of the metamorphosis of Poly- 

 pothrix amphibia, Zopf f. 



Besides these filaments we have seen many of Conferva-like 

 appearance (Plate V. figs. 3 and 4) , which are composed of cells 

 three or four times as long as broad (Plate V. figs. 3 and 4), 

 filaments with swollen yellowish cell-walls (Plate V. fig. 5), and 

 filaments which are composed of thicker-coated cells (Plate V. 

 figs. 6a &b). The cells of these filaments (figs. 5 and 6) sepa- 

 rate in a similar manner as before described. The result of the 

 fragmentation (at the ends of the filaments) is a Chroococcus or 

 G-loeothece-form (Plate V. figs. 9 and 10). The cells delineated in 

 figs. 9 and 10 spring from filaments of the shape and appear- 

 ance of fig. 6. The Qlceothece-forra springs from the Ghroococcus- 



* Schaarschuiidt, ' A chlorophyll^ a noyenyi sejtmag morphologiajahor ' 

 (Contributions to the Morphology of the Chlorophyll and Vegetable Nucleus) 

 1881, p. 46, fig. 17. 



t " Weitere Stiitzen fur meine Theorie von der Inconstauz der Spaltalgen 

 (Phycochromaceen)." Berichte d. deutschen Bot. Geaellsch. i. n. 7 (1883), 

 p. 319, t ix. 



LINN. JOUBN. — BOTANY, VOL. XXI. T 



