378 ALGiE FBOM CENTRAL AFRICA. 



Alg. iii. 2iG. Crass, cell, veget. 108-125 /x; long, zygosp. 141- 

 154 fx, lat. zygosp. 100-111 [x. Mwangadan Eiver, S. of Fuladoga. 



7. S. TERNATA Riparti in Bull. Bot. Nat. Fr. torn, xxiii. 1876, 

 162; Petit, Spirog. Knvir. Paris, 26, t. viii. figs, 4-7. Crass, cell. 

 veget. 54-57 /x; longit. 1-2^-plo major; crass, cell, fruct. usque 

 75 [x; long, zygosp. 78 /x, lat. zygosp. 48-54 [x. Inkuyuni, Kamassia. 



The diameter of the filaments and the dimensions of the zygo- 

 spores are a trifle small for this species, and come near those of 

 S. ncijlecta (Hass.) Kiitz., but as nearly all the fructiferous cells are 

 abbreviated and fairly inflated, it evidently belongs to S. ternata. 

 The latter species seems to have been separated only on account of 

 its more inflated and abbreviated fructiferous cells. 



8. S. DUBiA Kiitz. Tab. Phyc. v. t. 24; Eabh, Fl. Fump. Ah/. 

 iii. 243 ; Wolle, Frcshw. Alg. U. S. 220, pi. cxxxv. f. 11-12. Crass, 

 cell, veget. 43-48 /x; long, zygosp. 57-58 /x, lat. zygosp. 38-41 /x. 

 G. Laschan, Leikipia. 



Desmidiack^. 



9. Closterium Leibleinii Kiitz. Synops. Diatom, in TAnnfca, 

 1833, 596 ; Ealfs, Brit. Desm. 167, tab. xxviii. fig. 4. Lat. 18 fx. 

 Inkuyuni, Kamassia. 



10. C. LiTTORALE Gay, Essai Monog. Conj. 75, t. ii. fig. 17 ; 

 Note sur les conj. mid. France, Bull. Soc. Bot. France, 1884, 339. 



Var. CRASSUM, n.var. (Fig. 18). Var. cellulis multe crassioribus. 

 Long. 218 /x ; lat. 31 /x. Inkuyuni, Kamassia. 



The ''Closterium Leibleinii^ forma" described and figured by 

 Borge (Siissw. Chlor. Archangel, Bihang till R. Svenska Vet.-akad. 

 Handl. Band 19, 1894, 16, figs. 9, 10) belongs rather to C. littorale 

 Gay than to C. Leibleinii Kiitz. 



11. EuASTRUM vERRucosuM Ehmb. ; Ralfs, Brit. Desm. 79, 

 tab. 11, fig. 2. Long. 71 /x; lat. 69 /x ; lat. isthm. 16 /x. Mwan- 

 gadan River, S. of Fuladoga. 



12. E. spiNULOSUM Delp. '''africanum Nordst. Be Alg. et Char. i. 

 9, t. xvi. fig. 16. Long. 68, 79, 70, 71, 77 /x ; lat. 63-5, 64, 61, 61, 

 63 /x; lat. isthm. 14-5, 15, 14-5, 15-5, 16 /x ; crass. 38-5, 35 /x. 

 Mwangadan River, S. of Fuladoga. 



13. E. hexagonum, nov. sp. (Fig. 10). E. submediocre, 

 li-plo longius quam latum, medio profundissime constrictum, sinu 

 angusto-lineari extremo ampliato; semicelluhc subtrapezic^, angulis 

 rotundatis, lateribus biundulatis, elevationibus basalibus majoribus, 

 apicibus retusis in medio, elevationibus granulatis, in medio ad 

 basin cum aunulo granulorum majorum 7-8 circa granula 3 cen- 

 tralia ; a vertice visse oblongo-elliptic^, ad medium utrobique 

 tumidffi ; a latere visae pyramido-ovatfe, tumore basali utrobique. 

 Long. 48, 48-5, 53, 49 /x ; lat. 40, 40, 46, 40 /x; lat. isthm. 10, 10-5, 

 13, 9-5 fx; crass. 22, 22-5, 24, 21 /x. Mwangadan River, S. of 

 Fuladoga. 



This may be compared with Cosmarium alatum Kirchn. {Alg. 

 Schles. 153) and its var. gostyniense Racib. (Nonn. Desm. Polon. 17, 

 tab. xi. fig. 17), from which it differs in being twice as large, in 

 having fewer and larger granules, and in its different apex. 



