240 welwitsch's African freshwater algje. 



2. C. breviarticulata, sp, n. Filis solitariis vel gregariis, 

 algas majores aquaticas affixis, longitudine toto usque 380 jx, a base 

 ad apicem gradatira attenuatis ; vagina crassa lamellosa, plantis 

 vetustis brunneo-nigrescentibus ; trichomatibus pallide ffirugineis, 

 articulis brevissimis discoideis, diametro 4-5-plo brevioribus ; 

 heterocystis solitariis, basilaribus et hemisphajricis. Crass, fil. ad 

 bas. 15-16 fj., ad med. 11'5-12"5 /x ; crass, tricb. ad bas. 8*5 /*, ad 

 med, 5-5-7*5 /j.. 



Pungo Andougo. Epipbytica in Mow/eotia cnKjolensi ad ramulos 

 Podostemacearum in rivulis (Casalale) ; Marcb 1857. No. 105. 



Tbe babit, togetber witb tbe gradual attenuation of tbe fila- 

 ments, brings tins nearest to C. luhvcndem (Nag.) Born, et Flab. 

 (/. c. 365), but its smaller size, its sborter filaments, and its very sbort 

 cells easily distinguisb it. Tbe younger plants, wbicb bave only 

 attained a leugtb of about 100 /x and a tbickness of 5-5-7"5 /x, bave 

 tbeir cells only 2-3 times sborter tbau tbe diameter. It also comes 

 near to C. endophijtica Lemmermann in Forschumjsherk-hte Biulog. 

 Station zu Plan, iv. 184 (1896), but bas a different sbeatb and very 

 sbort filaments ; tbe beterocysts are also very distinct. 



3. C. epiphytica, sp. n. Filis minutis et epipbyticis algas 

 majores aquaticas affixis, solitariis vel subgregariis, longitudine 

 toto usque 250 /x (raro 350 /x), de base ad apicem gradatim attenu- 

 atis ; vagina subcrassa, byalina et acbroa ; tricbomatibus jerugineis 

 apice in pilum tenuissimum productis, articulis diametro subsequi- 

 longis, pauUo brevioribus basiu versus et lougioribus apicem versus ; 

 heterocystis basilaribus solitariis et parvis. Crass, fil. ad bas. 

 5-7*5 /x; crass, tricb. ad bas. 3-5-4 /x. 



Mossamedes. Epipbytica in (Edo(ionio sp., freq. in stagnis 

 puris ad ripas flum. Bero ; Aug. 1859. No. 190. 



2. DicHOTHRix Zanardini (1858). 



1. D. oLivACEA (Hooker) Born. & Flab. I.e. 375 (1886). Calo- 

 thrix oUvacea Hooker (1845). Crass, tricb. ad bas. 9'5-14"5 /x. 



Pungo Andongo. Inter Scytoueina Myochrous var. choro<iraphiciun, 

 in summis rupibus ; Febr. 1857. No. 6. Etiam inter Scytunenia 

 Millei ad rupes vulc. humectans prope Cacella ; Febr. 1857. No. 7. 



2. D. GYPSoPHiLA (Klitz.) Born. & Flab. /. c. 377-8 (1886). 

 Schizosiphon gypsophilus Kiitz. Phyc. (Jener. 234, t. 6, fig. 2 (1843). 

 Tbis seems to have been luxuriantly developed, and reached 5 mm. 

 in height ; the filaments were not incrusted with lime, as is often 

 the case with this species. Diam. tricb. 7-8 /x. 



Pungo Andougo. Inter Scytonema Myochrous var. chorogmphicimi, 

 in rupib. perpendic. ad latera boreal, et occid. de Pedra Songue ; 

 April 1857. No. 12. Inter Scytonema cincinnatiim var. cell do pic urn, 

 in pascuis spongiosis breve graminosis juxta rupes gig. prope Catete; 

 May 1857. No. 111. 



3. Gl(eotrichia J. Ag. (1842). 

 1. G. sethiopica, sp.n. Thallo plus minusve expanso, irregu- 

 lari, usque 3 cm. lato, olivaceo-viridi ; filis laxe associatis, pressione 

 facile secedentibus ; trichomatibus pallide olivaceo-viridibus, in 



