464 Wisconsin Academy of Sciences, Arts, and Letters. 
20. S. ornatus (Lemm.) nov. comb. (PI XXYI: Fig. 34.) 
S. perforatus var. ornatus Lemm. Lemmermann, 1910A, p. 294, 
309; Figs. 3-4. Brunnthaler, 1913, pp. 269, 171. 
“Coenobium 8-cellularum, foraminibus angnste linearibus, 
1.5-2 p latis, praeditum. Aculi cellularum exteriorum ca. 
20.5 p longi, subrecti vel distincte curvati. Membrana cel¬ 
lularum dense et subtiliter punctata.” 
The present system of recbgnizing a cell wall completely 
covered with spines as a specific character warrants the 
raising of this variety to specific rank. Known only from 
Paraguay. 
21. S. insignia (West and West) Chodat. (PI. XXVI: 
Fig. 32.) 
Chodat, 1913, p. 69. 
S. quadricauda var. insignis. West and West, 1895, p. 83; 
PI. V, Figs. 7-8. Balsamo, 1900, p. 266. 
“Var. cellulis 4 in seriem rectam dispositis unaquaequa 
cellula cum spina brevi singula, 2 simul ad dextram, 2 simul 
ad sinistram, cellulis terminalibus spina singula longa sig- 
moidea alternatim disposita; membrana punctato-granulato. 
Long. cell. 10.5-12.5 p; lat. cell. 4-5 p.” 
So careful a description of the position of the horns as 
West and West have given is entirely superfluous since my 
cultural work with species of S. longus Meyen, where there 
are horns on all of the cells of the coenobe, shows that both 
the number and position of the terminal horns is variable. 
The character which does separate this form from all other 
species of Scenedesmus is the punctate-granulate membrane 
in combination with horns on the ends of all cells. 
22. S. granulatus West and West. (PI. XXVI: Fig. 33.) 
West and West, 1897B, p. 500; PL VII, Figs. 1-2. G. S. West, 
1904B, p. 221. Brunnthaler, 1913, pp. 166, 170; Fig. 11. Chodat, 
1913, p. 24. 
“S. cellulis plerumque quaternis, oblongis, diametro cir- 
citer 3-plo longioribus, polis conicis, in seriem rectam con- 
junctis; membrana cellularum granulata, granulis minutis 
