364 xiv. rALMELLACE.E (West). [Pediastrum 
3. PEDIASTRUM Meyen (1829). 
1. P. Tetras Ralfs in Ann. Nat. Hist. xiv. 469, t. 12, f. 4 (1844) ; 
W. et G. S. West, I.e. 
Micrasterias Tetras Ehrenb. (1838). 
Hlii.la.— In paludibus exsiccandis : April 18G0. No. 176. Inter 
JTtricidariam, Morro de Lopollo : April 1860. No. 179. 
LlBONGO. — Ad margines Hum. Lifune : Sept. 1858. No. 204. 
4. OPHIOCYTIUM Nag. (1849). 
1. 0. majus Nag. Gatt. einz. Alg. 89, t. iv. A, fig. 2 (1849); 
W. et G. S. West, I.e. 
Pr\cu ANDONGO. — In stagnis prope Anbilla (Condo) ; March 1857. 
No. 177. 
2. 0. parvulum A. Br. Alg. Unicell. 55 (1855); W. et G. S. 
West, I.e. 
Brochidium parindum Perty. 
HuiLLA. — In uliginosis editioribus prope Humpata, Empalanca et 
Lopollo : May 1860. No. 15. 
PUNGO ANDONGO. — In stagnis prope Anbilla (Condo) : March 1857. 
No. 177- 
5. SCENEDESMUS Meyen (1829). 
1. S. denticulatus Lagerh. in Ofv. Kongl. Vet.-Akad. Fbrhandl. 
1882, no. 2, 61, t. ii. f. 13-16. 
Var. linearis Hansg. in Archiv. Naturwiss. Landesdurchf. 
Bbhm. Bd. 6, no. 268 (1888); W. et G. S. West in Journ. Bot. 
1897, p. 237. 
LlBONGO. — Ad margines num. Lifune ; Sept. 1858. No. 204. 
6. TETRAEDR0N Kiitz. (1845). 
1. T. minimum Hansg. in Hedwigia, 1888, 131 ; W. et G. S. 
West, I.e. 
Polyedrium minimum A. Br. in Rabenh. Fl. Europ. Alg. iii. 62. 
From the references given under the name T. minimum in his 
paper in " Hedwigia " it would appear that Hansgirg was under 
the erroneous impression that Braun described this plant in Rabh. 
Fl. Europ. Alg. as a Tetraedron. 
LlBONGO. — Ad margines num. Lifune ; Sept. 1858. No. 204. 
2. T. tropicum W. et G. S. West in Journ. Bot. 1897, p. 237. 
LlBONGO. — Ad margines flum. Lifune ; Sept. 1858. No. 204. 
This should be compared with T. reticulatum (Reinsch) Hansg. : 
in the latter species the membrane is not nearly so thick, and the 
scrobiculations are so large that the superficial part of the membrane 
only consists of a fine reticulation. 
3. T. tetragonum Hansg. I.e. (1888). 
Polyedrium tetragonum Nag. Gatt. einz. Alg. 84, t. iv. B, 
fig. 2 (1849). 
Var. inerme (Wille in Bihang t. K. Sv. Vet.-Akad. Handl. Bd. 
8, no. 18 (1884), 12, t. i. f. 25) ; W. et G. S. West, I.e. 
