Smith—Monograph of Scenedesmus. 
469 
Coenobia plerumque 4-cellularum. Apices cellularum ter- 
minalium cum singulo aculeo. Omnes cellulae coenobi cum 
singulo aculeo, latitudinaliter disposito. 
The arrangement of a single spine on one side only of the 
cell wall, in addition to spines on the four corners of the 
coenobe, is peculiar to this variety alone. 
25. S. longus Meyen. (PI. XXVIII: Fig. 54; PL: 
XXXI: Figs. 156-158.) 
Meyen, 1829, p. 774; Pl. XLIII, Fig. 28. Kiitzing, 1833, p. 607. 
Meyen, 1835, p. 250. 
Scenodesmus Naegelii. de Brebisson, 1856, p. 158. 
S. quadricauda var. Naegelii. Rabenborst, 1868, p. 65. de Toni, 
1889B, p. 566. Hansgirg, 1905, p. 458. Brunnthaler, 1907, p. 
207. Migula, 1907, p. 655. Brunnthaler, 1913, pp. 168, 171. 
S. caudatus forma setosus. Kirchner, 1878, p. 98. 
S. caudatus forma horridus. Kirchner, 1878, p. 98. 
S. quadricauda forma setosus. Lagerheim, 1883, p. 63. Chodat, 
1902, p. 214; Fig. 135. Pascher, 1903, p. 175. Collins, 1909, p. 
169. 
S. quadricauda forma horridus. Lagerheim, 1883, p. 64; PI. II, 
Fig. 19. Chodat, 1902, p. 214. Pascher, 1903, p.T/5. Collins, 
1909, p. 169. 
S. quadricauda var. setosus. Hansgirg, 1886, p. 115. de Toni, 
1889B, p. 566. Gutwinski, 1891, p. 302. Lagerheim, 1900, p. 10. 
Volk, 1903, p. 104. Hansgirg, 1905, P : 458. Volk, 1905, p. 65. 
Migula, 1907, p. 655. Selk, 1907, p. 98. Teodoresco, 1907, p. 130. 
Borge, 1909, p. 16. Gugliemetti, 1910, p. 32. Brunnthaler, 1913, 
pp. 168, 171. 
S. quadricauda var. horridus. Hansgirg, 1886, p. 115. de Toni, 
1889B, p. 566. Borge, 1895, p. 7. Boergesen, 1899B, p. 333. 
Schorler, 1900, p. 5. Boergesen, 1901A, p. 240. Borge, 1901B, 
p. 13. Fritsch, 1902, p. 582. G. S. West, 1904B, p. 220; Fig. 
92G. Hansgirg, 1905, p. 458. Migula, 1907, p. 655. Selk, 1907, 
p. 99. Borge, 1909, p. 16. West and West, 1909B, p. 184. Borge, 
1911, p. 204. Brunnthaler, 1913, pp. 168, 171; Fig. 17. 
S. caudatus var. setosus. Wolle, 1887, p. 172. Riabinine, 1889A, 
p. 303. Riabinine, 1889B, p. 47. Snow, 1903, p. 391. Dorogos- 
laisky, 1904, p. 224. Honigman, 1909, p. 54; PI. II, Fig. 7. 
S. caudatus var. horridus. Wolle, 1887, p. 172; PL CLVI, Fig. 
15. Riabinine, 1889A, p. 303. 
S. antcnnatus var. rectus. Wolle, 1887p*p. 172; PI. CLVI, Figs. 
16-17. de Toni, 1889B, p. 567. Stokes, 1893, p. 51. 
S. quadricauda var. bicaudatus. Hansgirg, 1890B, p. 9. Hans¬ 
girg, 1892, p. 230. Volk, 1903, p. 104. Volk, 1905, p. 65. Selk,. 
1907, pp. 68, 99, 108, 115. Migula, 1907, p. 655. Chodat, 1913,. 
p. 22. 
