45 



medio paullum turgidis, subventricosis, nonnunquam paullum oonstrictis, 

 apices versus sensim attenuatis, acutissimis, aut rectis aut varie curvatis. 



a. aciculare (Kh. aciculare A. Braun in Rabenh. Alg. \. AA2. 

 Ankistrodesmus uiuti.ssimus Archer in Soc. of. Xat. Hist. 1861. June 

 i>. 18. T. II. F. 44 — 56. Closterium Griffithii Berk. in Ann. oi' Xat. 

 Hist. XIII. p. 256. T. XIV. F. 2.), gracillimum , diametro maximo 

 15 — 20-plo longius, luteo-viride, plerumque singulum , acieulare, in 

 ntnimque finem acutissime cuspidatum, et rectum et leviter curvulum 

 vel sublunatum. v. v. 



Diam. max. l /i300— V«8o'" = 0,000066 — 0,00013". 



Hab. in aquariis , fossis, per Germaniam passim (ad Friburgum 

 Brisgoviense detexit cl. autor; prope Heidelberg: Mettenius ; in Saxonia : 

 Bulnheim, L. Rabenhorst; in Bohemia: Karl ; in Austria inferiore : 

 A. Grunow) ; in locis paludosis montosis Scotiae. 



b. fusiforme (Ankistrodesmus fusiformis Corda Alman. de Carlsb. 

 1838. p. 199. T. II. Rh. fasciculatum Ktz. ex p. Xaeg. einz. Alg. 

 p. 82. T. IV. C. 1. Rabenh. Alg. X. 172! sub. Xo. 547. et 1068! 

 Closterium gregarium Menegh. Consp. Alg. Eugan p. 17.), fusiforme, 

 inde a medio plus minus tumido (rarius attenuato) in apices acutos 

 sensim angustatum, laete vel luteolo-viride, diametro 12 — 20 plo lon^ius 

 solitarium, plerumque gregarie, fasciculatim congestum, medio connexum, 

 rectum vel plus minus curvatum. v. v. 



Diam. ^'mo— l /70o'" = 0,000059 — 0,000128". 



Hab. in fossis, stagnis totius Europae, maxime communis et mutabilis. 



c. falcatum (Micrasterias falcata Corda Alman. de Carlsb. 1835. 

 p. 121. T. II. F. 29. Staurastrum falcatum Ehrb. in Wiegm. Arch. 

 1836. p. 185. Closterium falcatum Menegh. in Linnaea 1840. p. 233. 

 Ankistrodesmus gregarius Breb. in litt. Ankistr. falcatus Ralfs Brit. 

 Desmid. p. 180. T. XXXIV. F. 3. Breb. List. des Desm. p. 158.), 

 fesiforme, gracile, utroque fine acutissime cuspidatum, curvatum vel 

 Bemilunare, 4 — 16 in fasciculos congregatum. v. v. 



Diam. max. l / 6 5o'" = 0,00013". 



d. sigmoideum (Rh. duplex Ktz. Phycol. germ. p. 144. Rh. triplex 

 Babenh. Krypt. Flor. v. Sachs. p. 134. Scenedesmus duplex Ralfs Brit. 

 Desmid. p. 193. X. 6. T. XXXIV. F. 17.), fusiforme, gracile, leviter 

 sigmoideum, singulum vel 2, 3 — 4 sub polis lateraliter connexum, 

 ceterum liberum. 



Hab. in iisdem cum autecedente locis, per totam Europam vulo-are. 



Rh. Braunii Kaeg. (in Ktz. Spec. p. 891.). Rh. omnium crassissi- 



mum, cellulis cylindraceo-fusiformibus; diametro 4 — 6 (rarius 7)-plo 



