Classification oj Green Algce. 2 13 
A REVISION OF THE CLASSIFICATION OF 
THE GREEN ALGJE 
BY 
F. F. Blackman, 
University Lecturer in Botany , Cambridge. 
AND 
A. G. Tansley, 
Assistant Professor of Botany , University College , London. 
{continued from page 192.) 
22. Sphcerozostna. Corda, 1835. 
/ 
Cells with a deep equatorial furrow;connected by minute 
tubercles or cone-shaped processes; elliptical or tri¬ 
angular in end view. Semi-cells oval in side-view. 
Chromatophore of two diverging plates in each semi¬ 
cell. 
23. Streptonema. Wallich, i860. 
Cells considerably broader than long, with a very 
deep equatorial furrow; connected by three hyaline 
cylindrical bands; in end-view 3-armed, each arm 
with a rounded swollen end. Chromatophore of three 
diverging plates in each semicell, each plate occu¬ 
pying an arm and branching into two in the swollen end. 
24. Aptogonum. Ralfs, 1848. 
Cells nearly square in side-view, with a very slight 
equatorial constriction, and a slight terminal con¬ 
cavity; in end-view triangular to quadrangular, or 
oval. Chromatophore of four to six or eight plates 
diverging from two, three or four pyrenoids in each 
semi-cell. 
25. Desmidium. Agardli, 1824. 
Cells oblong in side-view, broader than long, with a 
slight equatorial constriction; triangular or quad¬ 
rangular, rarely oval in end view. Chromatophore in 
each semi-cell, with as many pyrenoids as there are 
angles, and two parietal plates diverging from each 
pyrenoid. 
26. I’hymatodocis. Nordstedt, 1869. 
Cells approximately square in side-view, intimately 
connected by their flat ends; with a very narrow 
equatorial slit; in end-view 4-armed, with a tubercle 
on one side of each asymmetrical rounded arm. In 
side-view, each semi-cell the inverted counterpart of 
the other. 
