COSMARIUM. 35 



242. Cosmarium crenatum Ralfs. 

 (PI. XCVIII, figs. 9-12.) 



Cosmarium crenatum Ralfs in Ann. Mag. Nat. Hist. 1844, p. 394, t. 11, 

 f. 6 Tin part] ; Hass. Brit. Freshw. Alg. 1845, p. 365 ; Ralfs, Brit. Desm. 

 1848", p. 96, t. 15, f. 7 b and c [not 7 a] ; Arch, in Pritch. Infus. 1861, 

 p. 732; De Not, Desm. Ital. 1867, p. 47, t. 4, f. 34; Rabenh. Flor. 

 Europ. Alg. Ill, 1868, p. 165; Lund. Desm. Suec. 1871, p. 34; Nordst. 

 Desm. Spetsb. 1872, p. 29, t. 6, f . 7, 8 ; Desm. Arctoae, 1875, p. 38 ; Alg. 

 aq. dulc. et Char. Sandvic. 1878, p. 12 ; Kirchu. Alg. Schles. 1878, 

 p. 149; Wille, Ferskv. Alg. Nov. Semlj. 1879, p. 40; Boldt, Siber. 

 Chlorophy. 1885, p. 105 ; Cooke, Brit. Desm. 1886, p. 95, t. 37, f. 13; 

 Hansg. Prodr. Algenfl. Bohm. 1888, p. 195 ; De Toni, Syll. Alg. 1889, 

 p. 941 ; West, Alg. N. Yorks. 1889. p. 292 ; Alg. N. Wales, 1890, p. 289 ; 

 Alg. W. Ireland,' 1892, p. 150; Alg. Eiigl. Lake Distr 1892, p. 726; 

 Borge, Chlor. Norska Finmark. 1892, p. 10 ; Liitkem. Desm. Attersees, 

 1893, p. 553 ; Borge, Siissw. Chlor. Archang. 1893, p. 21 ; Borg. 

 Freshw. Alg. Ostgronl. 1894, p. 14; Roy & Biss. Scott. Desm. 1894, 

 p. 44; Gut\v. Flor. Gloii. Okolic Tarnapola, 1894, p. 86; Schmidle, 

 Beitr. alp. Alg. 1895, p. 388 ; Nordst. Index Desmid. 1896, p. 87 ; W. & 

 G. S. West, Alg. S. England, 1897, p. 488 ; W. & G. S. West, Alga-n. 

 Yorks. 190U, p!" 89; Borg. Freshw. Alg. Fseroes, 1901, p. 227; Borge, 

 Siisswasseralgen. Sud-Patagon. 1901, p. 22 ; Bohlin, Flor. Algol, d'eau 

 douce d. Acores, 1901, p. 65 ; W. G. S. West, Alg. N. Ireland, 1902, 

 p. 37 ; Him, Desm. Finland, 1903, p. 8 ; Borge, Alg. erst. Regnell. 

 Exped., II. Desmid. 1903, p. 92 ; Larsen, Freshw. Alg. E. Greenland, 

 19u4, p. 84 ; W. ct G. S. West, Freshw. Alg. Orkneys' and Shetlands, 

 1905, p. 22 ; Borge, Beitrage Alg. Schweden, 1905, p. 34 ; Teodoresco, 

 Mater, nor. alg. Kouman. 1907, p 177. 



Etiastrum crenatum Gay, Monogr. loc. Conj. 1884, p. 60. [not E. crenatum 

 Focke, Phys. Stud. 1847, p. 41, t. 1, f. 3, which = Cosmarium ortogonum 

 Delp. ; nor E. crenatum Nag. Gatt. eiiiz. Alg. 1849, p. 120, t. 7 A, f. 8, 

 which = Cosm. Naegelianum Breb. ; nor E. crenatum Perty, 1852, 

 which = Cosm. dovrense Nordst.] 



Cosmarium, crenatum forma tricrenata Boldt, Siber. Chlorophy. 1885, p. 

 105. 



C. crenatum. a. Ralfsiana Racib. Nonn. Desm. Polon. 1885, p. 76. 



C. crenatum e. major Racib. 1. c. 



Ursinella crenota Kuntze, Revis. gen. plant. 1891, p. 924. 



Cosmarium crenot urn var. psychophilum Schmidle, Lappmark Siisswasser- 

 algen, 1898, p. 29. 



C. crenatum forma sublsevis Schmidle, 1. c. p. 29. 



C. ordinatum Larsen, Ferskvandsalg. Yest-Gronl. 1907, p. 333, t. 7, f. 11. 

 [not C. ordinatum (Borg.) W. & G. S. West, 1896]. 



Cells rather small, 1^-1^ times as long as broad, 

 moderately deeply constricted, sinus linear but not 

 quite closed ; semicells pyrantidate- quadrate, with the 

 basal angles rectangular and slightly rounded, sides 

 3-crenate (or more rarely 4-crenate), apex truncate and 

 4-crenate, with 13 smaller subsidiary crenulations 

 within each lateral and apical crenation, internal 

 crenulations smooth or furnished with one or two 



