WELWITSCh's AFRICAN FRESH"WATER ALG.E. 265 



repens, in Mimosarum sylvis pr. Pedras de Guinga ; Jan. 1857. 

 No. 13. 



Stratum goldou- brown or violet ; branches rather scarce, usually 

 solitary, short, a little narrower than the primary filaments ; cells 

 sometimes a little longer than the diameter ; sheaths constantly 

 asperulate. Crass, fil. 24-2G /i; crass, trich. 15-18 /x. 



This is a most interesting species, having been previously seen 

 only from Italy by its original describer. 



3. S. Arcangelii Born. & Flah. I.e. 92 (1887). Crass, fil. 

 19-20 ix; crass, trich. 12-13-5 /x. 



Golungo Alto. Ad muscos prope fontem magn, ad Banza de 

 Soba Bango sitam ; Sept. 1855. No. 159. 



The following may be a larger form of this species : — 



Golungo Alto. Filaments forming somewhat irregular peni- 

 cillate tufts of a brown colour. Crass, fil. 23-25 /x; crass, trich. 

 14-5-17 /x. The specimens were not in a condition for satisfactory 

 identification. 



Ad fontem prope Banga de Bango, socialis cum Anthocero, etc. ; 

 Sept. 1855. No. 158. 



4. S. MiLLEi Born, in Born. & Thur. Notes Ahjolon. 147 (1880); 

 Born. & Flah. I.e. 93 (1887). Crass, fil. 18-5-25 /x ; crass, trich. 

 11-14-5 /x. Heterocysts sometimes subquadrate. 



Pungo Andongo. Ad rupes vulc. humectans prope Cacella, 

 inter Dichotrichem ollvaccam ; Febr. 1857. No. 7. 



5. S. ambiguum Kiltz. Spec. Ali/ar. 894 (1849) ; Tab. PJiijc. ii. 

 (1850-2), 7, t. 26, f. ii. ; Born. & Flah. /. c. 100 (1887). Crass, fil. 

 8-9-5 /x; crass, trich. 2-8-3-5 /x. 



Pungo Andongo. Inter S. Myoclirous var. clionujraphicum ; 

 Febr. 1857. No. 6. 



The heterocysts are about three times longer than broad, and 

 sometimes as many as three together. 



6. S. riGURATUJi Ag. S^ist. Ah/ar. 38 (1824) ; Born. & Flah. /. c. 

 101-3 (1887). Crass, fil. 16-20 //; crass, trich. 6-5-8 /x. 



Iluilla. In uliginosis editioribus prope Humpata, Empalanca 

 et Lopollo ; May 1860. No. 15. In gramiuosis paludibus juxta 

 rivulura de Lopollo ; April 1860. No. 180. 



7. S. Myocurous (Dillw.) Ag. JJispos. Ahjar. Suec. 38 (1812); 

 ]3orn. it Flah. I.e. 104-0 (1887). Conferva Myochrous Dillw. Brit. 

 Conferv. 37, t. 19 (1802). 



Var. cHoROGRAPHicuji, var. u. Var. vaginis uon ocrcatis. Crass, 

 fil. prim. 28-31 /x ; crass, ram. 21-25-5 /x; crass, trich. 7-5-11 /x. 



Pungo Andongo. Freq. et temp. pluv. (Dec. usque Apr.) Jjete 

 vegetans, in summis rupibus ; Febr. 1857. No. 6. Alga crecta 

 vel decumbens, cajspitose crescens, filamentis oculo nudo nigris, 

 penicillatim c centro adli. radiantibus, mox latas rupium gigant. 

 plagas, imprimis verticales, colore atro tingens, qua ex causa = 

 Pedra vegras de Pungo Andongo. 



Etiam ad latera boreal, et occid. de Pedra Songuc ; Apr. 1857. 

 No. 12. Alga terrestris vel potius rupcstris, eximie gregaria, 

 incrementi rapidissimi, juventnte et tempore per dies uebuloso, 



