162 CUSHMAN: DESMIDS FROM COLORADO 
PLEUROTAENIUM TRABECULA (Ehrenb.) Naeg. Einz. Alg. 104. 7. 
6.f. A. 1849. (PLATE 7, FIGURE 4.) 
Long, 5124; lat. ad bas. semicell. 31 4; lat. apic. 21 y; lat. 
ad. inflat. 34.54. (H.C. uo. 426.) 
CoOSMARIUM MARGARITIFERUM Menegh. Linnaea, 14: 219. 1840. 
Long. 474; lat. 42; lat. isthm. 15. (H. C. xo. 426.) 
Frequent. 
CosmariuM Borrytis Menegh. Linnaea, 14: 220. 1840. 
Long. 70 p; lat. 5g; lat. apic. 19.5 2; lat. isthm. 23 4. (H. 
C. no. 426.) 
CoSMARIUM LAEVE SEPTENTRIONALE Wille, Ofv. Vet.-Akad. Forh. 
1070: 43. fl. 72. f- 74. 1879. 
Long. 18; lat. 15 4; lat. isthm. 4.5-5 4. (H.C. mo. 422.) 
Common. 
CosMARIUM MENEGHINII Braunti (Reinsch) Hansg. Arch. Naturw. 
Landesd. Bohm. 6°: 195. 1888. 
Long. 27 y; lat. 21 7; lat. isthm. 6. Very similar to Wolle, 
Desm. U.S. ed. 2. i. 48. f. 28. 1892. (H. C. no. 422.) 
Cosmarium balteum Coloradense var. nov. (PLATE 7, FIGURE 5.) 
Long. 77.5 2; lat. 56 5 lat. apic. 19 7; lat. isthm. 184. Dif- 
fers from the species (C. balteum W. &. G. S. West, Trans. 
Linn. Soc. Bot. II. 5: 249. pl. 15. f. r.. 1896) by its 
smaller size, and with the central basal series represented 
by a single subcentral granule. (H. C. wo. 454.) 
EvASTRUM vERRUCOsUM Ehrenb. Abh. Akad. Wiss. Berlin, 1833: 
247. 1835; var. (PLATE 7, FIGURE 6.) 
Long. 1024; lat. 764; lat. lob. pol. 32y; lat. isthm. 25 4 
(H. C. no. 422.) Common. 
Evastrum Drpetta Ralfs, Ann. Nat. Hist. 14: 190. pl. 7. 4 ?: 
1844; var. (PLATE. 7, FIGURE 7.) 
Long. 110-116»; lat. 434; lat. lob. pol. 25 ~; lat. isthm. 15 4 
Very much like the smaller variety figured by Wolle (Desm. 
U.S. ed. 2. p/. 33. f. 9), but the polar lobe is much broader. 
In Wolle’s figure the ratio of the polar lobe to the diameter 
is 1 to 2.5, in the Colorado specimens 1-1.7.  (H. C. ”%- 
- 426, 451, etc.) Very common. 
