OF THE THIRD TANGANYIKA EXPEDITION. 159 
244. GoMPHONEMA AFRICANUM, sp. п. (PI. 8. fig. 13.) 
G. magna ; cellula ut in visa aspectu valvulari ovato-lanceolata, lateribus 
inferioribus leviter concavis, lateribus superioribus convexis, apice subacuto, 
ad basin angulari-rotundata, cum stigmati singulo unilaterali prope nodulum 
centralem, platea axiali angusta in medio non dilatata, striis 10-11 in 10 р, 
transversis sed radiatis prope apicem ; in visa aspectu cingulato cuneata, basi 
et apice rotundato-truncato, lateribus levissime biundulato. 
Long. 102-128 ш ; lat. max. 23-28 ш; lat. ар. aspect. cingul. usque ad 
34 u. 
Tanganyika.—Among Chetomorpha Linum, Kütz., floating on surface of 
Kituta Bay (26 Aug. 1904 ; no. 79). On rocks, in shallow water, near Mbete 
(29 Sept. 1904 ; no. 114). 
This species should be compared with G. oxycephalum, Cleve, Synops. Navic. 
Diat. i. (1894) p. 187, t. 5. fig. 10. 
Family COCCONEMACEZ. 
Genus COCCONEMA, Zhrenb. 
245. CoccoNEMA LEVE, (№9.) nob—Cymbella levis, Ndg. in Kütz. Sp. 
Alg. (1849) p. 59 ; Van Heurck, Synops. Diat. Belg. p. 62, t. 3. fig. 7. 
Tanganyika.—In plankton, Lofu River (5 Nov. 1904 ; no. 124). 
246. CoccoNEMA LEPTOCEROS, Ehrenb. in Phys. Abh. Akad. Wiss. Berl. 
1841 (1843), p. 412.— Cymbella leptoceros, Rabenh. Süssw. Diat. t. 7. fig. 14 
(1843) ; Van Heurck, l. c. p. 62, t. 2. fig. 18. 
Victoria Nyanza.—Near Bukoba (17 Apr. 1905 ; no. 248). 
247. CoccONEMA GROSSESTRIATUM, (О. Müll.) nob.— Cymbella grossestriata, 
0. Müll. т Engl. Bot. Jahrb. xxxvi. (1905) p. 154, t. 1. fig. 13. 
Var. TANGANYIK®, var. п. (РІ. 8. fig. 9.) 
Var. margine ventrali convexiore, polis obtusioribus sed levissime productis ; 
striis validis et latis, 2*5 in 10 р (ad pol. 4 in 10 д). 
Long. 74 р; lat. 29 р. 
Tanganyika.—In plankton, near Kassanga (14 Nov. 1904; no. 159) and near 
Kirando (1 Dec. 1904 ; no. 175). 
This is a handsome Diatom with exceedingly coarse strize composed of large 
granules. The specimens observed from Tanganyika were stouter and more 
swollen on the ventral margin than Müller's Nyasa specimens, the strize being 
even coarser. 
948. Соссомема TURGIDUM, (Greg.) nob.—Cymbella turgida, Greg. (1856); 
Cleve, Synops. Navic. Diat. 1. (1894) р. 168. 
, Nyasa.—In swamp, Kota Kota (20 June, 1904 ; no. 18). 
Tanganyika.—In swamp, Mrumbi (27 Dec. 1904 ; no. 196). 
