OF THE THIRD TANGANYIKA EXPEDITION, 97 
Hyalotheca mucosa, (Dillw.) Ehrenb. 
Scenedesmus denticulatus, Lagerh., var. linearis, Hansg. 
" obliquus, (Turp.) Kütz. 
Ankistrodesmus falcatus, (Corda) Ralfs. 
Spherocystis Schroeteri, Chodat. 
Bacillariez. 
Synedra Ulna, (Nitzsch) Ehrenb. 
» » var, splendens, (Kütz.) Van Heurck. 
Achnanthes linearis, (W. Sm.) Grun. 
Vanheurckia vulgaris, (Thw.) Van Heurck. 
Gomphonema parvulum, (Kütz.) Grun. 
Cocconema gracile, (Rabenh.) G. S. West. 
» leve, (Nüg.) nob. 
Surirella robusta, Ehrenb., var. splendida, (Ehrenb.) Van Heurck. 
Myxophycesz. 
Lyngbya bipunctata, Lemm. 
III SYSTEMATIC ACCOUNT OF THE ALGÆ OF THE COLLECTIONS. 
This portion of the paper is devoted to a complete systematic account of 
all the Algæ observed in Dr. Cunnington's collections, those from pools and 
swamps, from scrapings of wet rocks, &c., being included along with the 
plankton. The collections from Tanganyika and the vicinity were the most 
numerous, and this fact accounts largely for the greater number of species 
recorded from that area. The few collections from the vicinity of Victoria 
Nyanza contained a relatively greater variety of Algz, and had more collec- 
tions been made in the area, a very rich Alga-flora would undoubtedly have 
peen revealed. 
The absence of plants belonging to the Stigonemacex is somewhat remark- 
able, the genus Nostochopsis being the only representative of the family 
observed. Species of Hapalosiphon are of general occurrence in the swamps 
and marshes of the tropics, not to mention certain of the bog-loving and 
rupestral Stigonema, and four species of the first-mentioned genus have 
already been recorded from Tropical Africa. 
Several of the Algw observed have been excluded from this account owing 
to the impossibility of identifying them with any degree of certainty. Such 
species were mostly in a fragmentary condition, and amongst them were two 
species of Nostoc from the Tanganyika area, а species of Calothrix from Deep 
Bay, Nyasa, and a Batrachospermum from the Lofu River, Tanganyika. 
One genus, thirty-six species, and eighteen varieties and forms are here 
described for the first time. 
LINN. JOURN.—BOTANY, VOL. XXXVIII. 
