Marks , employed for classifying the Schizomycetes. 113 
(IS) Containing phycochrome. 
Calothnx (Ag.). ) jqi aments cylindrical. 
Scytonema (A g.), &c. j 
Merizotnyria (Kg.). 
Mastigocladus (Cohn). 
Schizosiphon (Kg.). ) Filaments tapering, 
Geocyclus (Kg.), &c. f riding-whips. 
Filaments moniliform. 
like 
It will be remembered that Cohn was attempting a scheme 
to embrace the whole of the Schizophyta, and not merely the 
Schizomycetes ; and although we now exclude the forms 
containing ‘ phycochrome,’ as relegated to their proper posi- 
tion among the lower Algae, it seemed advisable to retain 
them in the above scheme, as Cohn did in his classical memoir. 
It will be obvious to all who are acquainted with the subject 
that Cohn’s chief divisions have always afforded important 
bases for subsequent systems of classification of these or- 
ganisms ; though it was soon shown, by Koch, Prazmowsky, 
and others, that the zoogloea cannot be employed as a distin- 
guishing mark in the sense Cohn employed it, and other 
characters had to be sought for the primary divisions. I 
now propose to set forth some of the best known of these 
systems, which will at the same time mark the main points 
of progress attained since Cohn’s time. 
In 1881, Winter published his system, designed for his 
edition of Rabenhorst, and I append his tabular resume — or 
key — in its original form, as it best illustrates the author’s 
attempt to make a definite Flora for the group. 
TABLE II.— Winter, 1881. 
1. Cells spherical or ovoid . . . .2 
Cells cylindrical — short or long . . .5 
Cells lanceolate, ribbon-like, spirally coiled . Spiromonas. 
2. Cells isolated, or in chains, or grouped in 
amorphous slime ..... Micrococcus. 
Cells in large numbers, united into colonies 
with definite contour . . . .3 
I 
