150 Avierican Quarterly Microscopical Journal. 



filaments form a flat, discoidal, cellular layer. Swarm- 

 spores form in the outer cells ; oogonia are scattered on 

 the surface or erect. 



C. sceutata, Breb. Peripheral cells with hair-like ends. Fil- 

 aments growing into a circular disk. 



C. pulchella, Rbh. Peripheral cells devoid of hairs, other- 

 wise like the former. 



2. Gen. Chcetophora, Schrk. Branched filaments with tufted 



branches, in soft gelatinous layers on water plants, etc. 

 Stem and branch cells transparent with transverse bands 

 in the middle (similar to both of the following genera); 

 branches made up of cells rich in chlorophyll. These 

 produce the swarm-spores. Terminal cells of the 

 branches awl-like or bristly, not fruiting and clear. 

 [Filaments combined by gelatin into a compound frond.] 

 Ch.pisiformis, Ag. Globose. Size of a pea. [Formed of 

 numerous erect, radiating, sub-parallel filaments, branch- 

 ing to the surface.] 

 Ch.endivicefolia, Ag. Layer flat, leathery. 



[Harvey says, frond elongated, much branched, branches linear, 

 scattered, or fasciculate, very patent, dichotomous, or pinnate, or 

 secondly ramulose, longitudinal filaments parallel, hyaline, or trans- 

 versely banded, emitting at short intervals, tufts of multifid bright- 

 green ramuli.] 



3. Gen. Stigeocloneum, Ktz. Jointed filaments, branched, with- 



out gelatinous matrix, branches ramifying, as large 

 as the stem, formed of colorless cells with a transverse 

 band. Branches scattered, close, seldom in tufts, and 

 flabby, with short green cells in which swarm-spores 

 form singly, out of the entire contents. Branches 

 turned about their axes, terminal cells often with bodkin 

 or hair-like bristles. Forms small, green flocks on blades 

 of grass, twigs, etc. 



St. lubricum, Lgb. Cells of the stem 0.0 1 d., 2-3 times as long. 

 Terminal cells generally awl-shaped. 



St. p?-otensum, Dillw. Stem-cells 0.015 ^ ! ^^^ ^s long, or twice 

 as long, slightly turgid. Terminal cells of the branches 

 bristly. 



4. Gen. Draparnaldia, Bory. Similar to the former, but 



branches smaller than the stem. [Filaments separate, 

 only differs from Chcetophora hy absence of a gelatinous 



