38 welwitsch's African freshwater alg^. 



membrana crassissima et lamellosa, acliroa, cum processibns solidis 

 mamillatis achrois 4, plerumque in^qualibus, unoquoque in unum 

 cellulfB coujugattTB pvojecto. Crass, cell, veget. 6-8 /a; diam. zygosp. 

 siue proc 21-27 /^ ; crass, membr. 3-6 jx; long. proc. 3-18 yu.. 



Huilla. In paludibus exsiccaudis ; April 1860. No. 176. 



This cliaractei'istic species belongs to the section Staurospermum ; 

 in maturely conjugated specimens this can only be inferred from 

 the genuflexed conjugating ceils, but the young zygospores are sub- 

 rectangular or subquadrate. The four processes present on the 

 zygospores are developed very early, considerably before the zygo- 

 spores are ripe, and are rarely of equal langth ; they are of the 

 same diameter as the vegetative cells, and fit into them very closely. 



2. M. (§ Staurospermum) irregularis, sp. n. M. cellulis 

 vegetativis diametro 5-6 plo longioribus, cellulis conjugatis sub- 

 curvatis ; zygosporis maturis irregularibus, subrectangularibus vel 

 trapeziformibus, exospora crassa achroaque, ad angulos in processus 

 longitudiuum varium (nonnunquam cum 1-3 processum usque 29 /a) 

 productis, mesospora crassa, flava vel flava-brunnea, punctata. 

 Crass, cell, veget. 13*5-15 /x; long. max. zygosp. c. proc. irreg. 

 38-63 /x, lat. max. 42-48 /x. 



Pungo Andongo. In pascuis spongiosis breve graminosis juxta 

 rapes gigant. prope Catete ; May, 1857. No. 111. 



The nearest species to this is M. cdpucina (Bory) Ag., from 

 which it is distinguished by its size, its colour, and its curious 

 zygospores. 



3. M. (§ Craterospermum) angolensis, sp. n. M. cfespitibus 

 laete viridibus dense intricatis ; cellulis vegetativis diametro 4-5-plo 

 longioribus, pyrenoidibus minimis 4-6 (plerumque 5), serie plus 

 minusve irregulari intra chromatophorum ; zygosporis parvis breviter 

 cylindricis (a fronte visis quadratis), lateribus coucavis, angulis 

 acutis ; cellulis conjugatis genuflexis. Crass, cell, veget. 25-29 /a ; 

 diam. zygosp. 19-21 fx. 



Pungo Andongo. Ad ramulos Podostemacearum in rivulis 

 (Casalale), inter (Edo(/onium Rothii f. major ; March 1857. No. 105. 



This species differs from M. Itetevirens (A. Br.) Wittr. chiefly in 

 the chromatophores each possessing a much fewer number of 

 pyrenoids, and in the much smaller zygospores. 



4. MouGEOTiA sp. Crass, cell, veget. 19-21 //, ; diametro 4-6- 

 plo longioribus. 



Huilla. Ad culmos Eleocharidis fluitantis in rivulis de Morro 

 de Lopollo (5300 ped. altit.) ; Febr. 1860. No. 188. 



Mossamedes. Freq. in stagnis puris ad ripas flum. Bero; Aug. 



1859. No. 190. 



5. MouGEOTiA sp. Crass, cell, veget. 20-25 //. 



Huilla. Inter Utriculariam ecalcanitam, Morro de Lopollo; April 



1860. No. 179. 



Conjugation incomplete ; conjugating cells much bent. 



2. GoNATONEMA Wittr. (1878). 

 1. G. tropicum, sp. n. G. cellulis vegetativis diametro circiter 

 7- (6-8)-plo longioribus ; aplanosporis permagnis, a fronte visis 



