Cosmarium] xi. desmidiace^e (West). 351 



This is somewhat like C. nitidulum De Not. in form, but the very- 

 thick and scrobiculate membrane easily distinguisLes it. 



15. C. trifossum W. et G. S. West in Journ. Bot. 1897, p 116, 

 t. 367, f. 19. 



HuiLLA. — Inter Utricular iam, Morro de Lopollo ; April 1860. 

 No. 179. In paludibus exsiccandis ; April 1860. No. 176. Etiam in 

 graminosis paludosis juxta rivulum de Lopollo ; April 18G0. No. 180. 



The three shallow notches seen in the front view of each semicell 

 are due to the presence of three grooves running at right angles to- 

 both the longitudinal and transverse axes. 



16. C. galeritum Nordst. in Vidensk. Medd. Naturh. Foren. 

 Kjoben. 1869, No. 14-15, 209-210, t. iii. f. 26 (1870); W. et G. 

 S. West in Journ. Bot. 1897, p. 116. 



LiBONGO. — Ad margines flum. Lifune ; Sept. 1858. No. 204. 



17. C. nitidulum Not. Desm. Ital. 42, t. iii. f. 26 (1867). 



C. rectosporum W. B. Tuin. in K. Sv. Vet.-Akad. Handl. Bd. 

 25, no. 5, 69, t. x. f. 16 (1893). 

 Var. minor W. et G. S. West, I.e. 

 HuiLLA. — In paludibus exsiccandis ; April 1860. No. 176. 



18. C. scenedesmus Delp. in Memor. Accad. Sci. Torino, ser. 2, 

 XXX. 5-6, t. vii. f. 28-34 (1878). 



Var. dorsitruncatum Nordst. in K. Sv. Vet.-Akad. Handl. Bd. 

 xxii. no. 8, 59, t. iii. f. 15 (1888) ; W. et G. S. West, I.e. 

 A small form with a perfectly smooth membrane. 

 HuiLLA. — In paludibus exsiccandis ; April 1860. No. 176. 

 LiBONGO.^Ad margines flum. Lifune ; Sept. 1858. No. 204. 



19. C. sethiopicum W. et G. S. West in Journ. Bot. 1897, 

 p. 116, t. 367, f. 20. 



Pun GO Andongo. — Inter Scytonema Myochroinf v. chnrographicum et 

 Dichotrichpm gi/psophilam ad latera boreal, et occid. de Pedra Songue ; 

 April 1857. No. 12. 



HuiLLA. — Inter Porjihyrosiphonem Notarisi prope lacum Ivantala ; 

 March 1860. No. 17. 



In outline this species calls to mind C. recta >i(inl(i/re Grun. 1868 

 (= C. Gotlandii'iim Wittr. 1872), but the more angular semi-cells, the 

 much broader isthmus, and the plications present on the upper half of 

 the semi-cells, at once distinguish it. 



20. C. pseudoprotuberans Kirchn. in Cohn, Kryptog. -flora von 

 Schlesien, Zweit. Bd. 150 (1878); Nordst. in Of v. K. Vet.-Akad. 

 Forh. no. 3, 8, t. vii. f. 3 (1885) ; W. et G. S. We.st, I.e., p. 117. 



A small form agreeing with var. pygvicntm Gutw. (Flora 

 glonow okolic Lwowa, 54, t. ii. f. 9) in dimensions, but of the 

 same form as the type. 



HuiLLA.— In paludibus exsiccandis ; April I860. No. 176. 



21. C. polygonum Arch, in Pritch. Infus. 732 (1861). 

 Euastrum polygonum Niig. Gatt. Einz. Alg. 120, t. 7a, f. 9 (1849). 

 Var. exile W'.'et G. S. West in Journ. Bot. 1897, p. Il7. 



