476 Wisconsin Academy of Sciences, Arts, and Letters. 
1908, p. 163. Andrews, 1909, p. 379. Brown, 1909, p. 335. Honig- 
mann, 1909, p. 54. Bethge, 1911, p. 498. 
Arthrodesmus quadricaudatus. Ehrenberg, 1836. Ehrenberg, 
1838, p. 150; PI. X, Fig. 16. Bailey, 1841, p. 292; PI. I, Figs. 
18A-18B. Pritchard, 1841, p. 189. Cantor, 1842, p. 493. Ehren¬ 
berg, 1843, pp. 337, 338. Pokorny, 1854, p. 58. 
S. quadricaudatus. de Brebisson, 1839, p. 271. Hassall, 1845, 
p. 392; Pl. XCII, Fig. 12. Ralfs, 1845, p. 402; PI. XII, Fig. 4. 
Ralfs, 1846, p. 159; PI. XV, Fig. 4. Reinsch, 1877, p. 238. W. 
West, 1888, p. 748. Lemmermann, 1891, p. 148. Lemmermann, 
1893, p. 524. Lemmermann, 1895A, p. 41. Lemmermann, 1895B, 
p. 296. Tassi, 1895, p. 12. Schroder, 1896, p. 46. Lemmermann, 
1897, p. 108. Strohmeyer, 1897, p. 6. Lemmermann, 1898A, 
p. 192. Balsamo, 1900, p. 267. Dalla Torre und von Sarnthein 
1901, p. 35. Kellermann, 1902, p. 223. Snow, 1903, p. 391. 
Zacharias, 1903A, p. 203. 
Scenodesmus caudatus. Kiitzing, 1845, p. 139. Kiitzing, 1849, 
p. 186. Nageli, 1849, p. 91; PI. V, Figs. 2A-2E. Rabenhorst, 
1850, p. 517. Kirchner, 1891, p. 18. Conn and Webster, 1908, 
p. 35; PI. VI, Fig. 38. 
Scenodesmus quadricauda. de Brebisson, 1856, p. 158. Archer, 
1861, p. 753; PI. I, Figs. 40 ,41, 43. 
S. caudatus forma typicus. Kirchner, 1878, p. 98. 
S. quadricauda forma typicus. Lagerheim, 1883, p. 63. Chodat, 
1902, p. 213; Figs. 133-134. Collins, 1909, p. 169. Petersen, 1911, 
p. 160; Fig. 3. 
S. quadricauda var. genuinus. Hansgirg, 1886, p. 115. de Toni, 
1889B, p. 566. Volk, 1903, p. 103. Hansgirg, 1905, p. 458. 
Stadler, 1905, p. 236. Volk, 1905, p. 65. Selk, 1907, pp. 8, 57, 
68, 79, 85, 91, 94, 98, 103, 108, 115. Gugliemetti, 1910, p. 32. 
S. caudatus var. typicus. Wolle, 1887, p. 172; PI. CLVI, Figs. 
11-14. Webber, 1889, p. 1012. Dorogoslaisky, 1904, p. 224. 
S. obtusus var. cornutus. Franze, 1892, p. 149; PI. Ill, Fig. 7. 
de Wildemann, 1897B, p. 78. 
S. variabilis var. cornutus. de Wildemann, 1893A. de Wilde¬ 
mann, 1893B, p. 91. Schmidle, 1895, p. 305. de Wildemann, 
1895, p. 26. de Wildemann, 1896. de Wildemann, 1897A, p. 61. 
de Wildemann, 1897B, p. 49. de Wildemann, 1899, p. 11. Fournier, 
1903, p. 28. Schodduyn, 1909, p. 166. 
S. quadricauda forma genuinus. Pascher, 1903, p. 175. 
S. quadricauda var. typicus. Migula, 1907, p. 655. Teodoresco, 
1907, p. 129. Brunnthaler, 1913, pp. 168, 171; Fig. 16. 
Scenodesmus caudatus var. typicus. Conn and Webster, 1908, 
p. 35; PI. VI, Fig. 33. 
S. genuinus. Kofoid, 1910, p. 31. 
“Coenobiis e cellulis 2-8, cylindraceo-oblongis, utroque 
polo obtuso-rotundatis serie aut simplici aut duplici alter- 
nante dispositis constitutis; cellulis omnibus rectis, medianis 
