444 Wisconsin Academy of Sciences , Arts , and Letters. 
Scenodesmus caudatus var. ecaudatus. Kutzing, 1849, p. 186. 
Scenodesmus obtusus var. binarius. Kutzing, 1849, p. 185. 
Scenodesmus obtusus var. biternarius. Kutzing, 1849, p. 185. 
Scenodesmus obtusus var. quaternarius. Kutzing, 1849, p. 185. 
Scenodesmus obtusus var. obliquus. Kutzing, 1849, p. 185. 
Scenodesmus obtusus var. ternarius. Kutzing, 1849, p. 185. 
Scenodesmus obtusus var. octonarius. Kutzing, 1849, p. 185. 
Scenodesmus obtusus var. alternans. Kutzing, 1849, p. 185. 
Scenodesmus obtusus var. obliquus dunlex. Kutzing, 1849, p. 
185. 
Scenodesmus obtusus var. Leibleinii. de Brebisson, 1856, p. 160. 
S. obtusus var. ecornis. Franze, 1892, p. 149; PI. Ill, Figs. 4, 
13-14. de Wildemann, 1897C, p. 78. 
5. variabilis var. ecornis. de Wildemann, 1893A. de Wilde¬ 
mann, 1893B, p. 91. Schmidle, 1895, p. 305. de Wildemann, 
1895, p. 26. de Wildemann, 1897A, p. 60. de Wildemann, 1897B 
p. 49. de Wildemann, 1899, p. 11. Schmidle, 1900B, p. 126. 
Schmidle, 1902B p. 125. Fournier, 1903, p. 28. Schodduyn, 
1909, p. 166. 
S. bijugatus var. seriatus. Chodat, 1902, p. 212. Migula, 1907, 
p. 658. Brunnthaler, 1913, pp. 169, 172. 
S. obtusus var. seriatus. Reinhardt, 1905, p. 26. 
S. bijugatus forma seriatus. Volk, 1905, p. 64. Larsen, 1907B, 
p. 104. 
Steinella Graevenitzii. Bernard, 1908, p. 189; PI. XIV, Figs. 
463-466. 
“Coenobiis 4-8 cellularibus; cellulis oblongo-ellipticis vel 
ovatis, utroque polo obtuso-rotundatis, aculeis carentibus, 
7-18 x 4-7 (raro 10) y, in seriem simplicem, rectam vel ob- 
liquam arete laxeve conjunctis.” 
A well known species which I have not obtained in pure cul¬ 
ture. The cells of several cultures which at first appeared 
to be S. bijuga were found on closer examination to have 
small spines on the ends, and it is probable that various in¬ 
vestigators who have reported the species have failed to 
note these horns on coenobes with obtuse cells and so called 
the species S. bijuga. I have found the species fairly abun¬ 
dant in nature in this vicinity and can not explain why I 
have been unable to obtain it in pure culture. 
The cells are arranged in either a linear or sub-alternating 
series. A strain was isolated with the cells constantly in 
two series, a condition which is found in nature and regarded 
by many as a normal variation of S. bijuga but I prefer to 
consider this as a variety ( platydisca ) of S. arcuatus Lemm., 
