COSMARITJM. 161 



156. Cosmarium Brebissonii Menegli. 

 H (PL LXX1X, figs. 10, 11.) 



Cosmarium Brebissonii Menegli. in Desinaz. PI. crypt. France, 1838, fasc. 

 19, no. 903 ; Synops. Desm. 1840, p. 219 ; Ealf s, Brit. Desni. 1848, p. 100, 

 t. 16, f. 3 ; Arch, in Pritch. Infus. 1861, p. 732 ; Eabenh. Flor. Europ. 

 Alg. Ill, 1868, p. 158 ; Lund. Desm. Suec. 1871, p. 27 ; Delp. Desni. 

 subalp. 1877, p. 30, t. 9, . 17-22 ; Wolle, Desm. U. S. 1884, p. 75, t. 13, 

 f. 10-11; Cooke, Brit. Desm. 1887, p. 100, t, 38, f. 2; Hansg. Prodr. 

 Algenfl. Bohni. 1888, p. 200; De Toni, Syll. Alg;. 1889, p. 983; West. 

 Alg. N. Wales, 1890, p. 289 ; Alg-. W. Ireland, 1892, p. 152 ; Alg;. Eiigl. 

 Lake Distr. 1892, p. 726 ; Roy & Biss. Scott. Desm. 1894, p. 44 : Nordst. 

 Index Desm. 1896, p. 67 ; West & G-. S. West, Alg. S. England, 1897, 

 p. 488 ; Alga-fl. Yorks. 1900, p. 71 ; Borg. Freshw. Alg. Faroes, 1901, 

 p. 228 ; West & G-. S. West, Alg. X. Ireland, 1902, p. 37 ; Scott, Freshw. 

 Plankton, I, 1903, p. 527 ; Freshw. Alg. Orkneys and Shetlands, 1905, 

 p. 19 ; Comp. Study Plankton Irish Lakes, 1906, p. 85. 



C. .Boirj/iisMenegh. var. Brebissonii (Menegli.) Rabenh. Krypt. Fl. Sachs. 

 1863, p. 200. 



Didymidium (Cosmarium} Brebissonii Reinsch, Algeiifl. Franken, 1867, 

 p. 122. 



Cosmarium Brebissonii Menegli. forma subtumida Xordst. Norg'es Desm. 

 1873, p. 12. 



C. Brebissonii var. horrida Jacobs. Desm. Daneni. 1876, p. 194. 



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



Cosmarium Brebissonii forma erosa West, Alg. W. Ireland, 1892, p. 152, 

 t. 21, f. 6 ; Alg. Engl. Lake Distr. 1892, p. 726 ; West & G-. S. West, 

 Alg. S. England, 1897, p. 488 ; Alga-fl. Yorks. 1900, p. 71. 



Cells large, about 1^ times as long as broad, deeply 



constricted, sinus narrowly linear with a dilated ex- 



.' 



tremity ; semicells semi-elliptic, basal angles rounded, 

 apex flattened and subtruncate ; densely coyered witli 

 large conical granules (or papillae), arranged in no 

 definite order, but reduced at the apex, from the 

 middle of which they are entirely wanting. Side yiew 



C/ /' 



of semicell subcircular with a depressed (almost 

 flattened) apex. Vertical yiew elliptic -subrhomboid. 

 or elliptic with widely tumid sides, the space in the 

 middle of the apex which is destitute of granules 

 clearly visible, and also the reduction in size of the 

 granules in the vicinity of the apex. Cell-wall be- 

 tween the large granules densely and strongly punc- 

 tate. Chloroplasts axile, each with two pyrenoids. 



Zygospore (consult Arclu: j r in 'Quart. Journ. Micr. 

 Sci.' xiii, 1872, p. 100). 



VOL. III. 11 



