per or moving granules: frond smooth and colouiicss. no suture; 

 chlorophyll in one pale green band reaching close to the ends, and 

 having at the middle of the frond a semielliptical colourless space, 

 as if scooped out of one side, similiar to what is seen in C. obtu- 

 sum Bréb.; starch granules 4-Ó in one row, Dim. 128-192 «3 j.. 



C. piisììhim Hantzsch [i major n. v. p. 5ó. Smooth and colourless; 

 six tirnes as long as broad, Dim. 96-100 « ló u.; breadth of obtuse, 

 rounded end 7 y.. 



Penium Libellula Focke /3 intermedìiim n. v. p. óo. Precisely si- 

 milar to the type, but only half as large, or rather less. Dim 118-128 



« 25 7,-29 'J. 



Weil «this form appears to connect Libellula Focke with 

 Navi cu la Bréb.», sind die Verf. geneigt diese beiden als extreme 

 Formen einer Art zu betrachten. 



Cosinocladium perissuin n. s. p. Ó2, T. II, f. 14. Very minute; 

 nearly as broad as long; constriction tolerably deep and opening 

 widely; sides semicircular; ends rather flattened, cell-walls very pel- 

 lucid, and sometimes broAvnish in colour. Zygosp. large in propor- 

 tion to the fronds, extremely irregular in shape, and reddish brown 

 in colour. Grows apparently in free groups. Dim. i 2-1 3 » 10- 1 2 « 6-7 /. 



Zygosp. l5-20 a. 



Bei folgenden Arten werden Zygoten beschrieben : Micraste- 

 rias angulosa Hantzsch. Zygosp. large, globose; spines stout, bi-, 

 tri-, and quadrifurcate at their apices, and not very numcrous. Diam., 

 without sp., 1 14-1 16 /.; length of sp. 32 y. (T, IV, f, 2). 



Euastrum ampullaceum Ralfs. Zygosp. globular, with nu- 

 merous short, conical, acute spines. Diam. without sp., 64- òo u-., 

 length of sp. 6,4 a. | 



E. ansatum Ralfs. Zygosp. globular, with numerous short, stout, 

 abruptly sharp-pointed spines. Diam. without sp. 38,4 P-^ length of 



sp. 6,4 [).. 



E. didelta Ralfs. Zygosp. globular, very thick-walled; spines 

 not numerous, short, stout, and blunt. Diam. without sp. 73,6 a.; 

 length of sp. 12,8 p. — Die Zygote dieser Art ist spater in Turner 

 Fresh-wat. alg. Tab. XI, fìg. 7 abgebildet. Zygoten sind auch von 

 Archer in Quart. Journ Micr. se. voi. Vili, iSó8 und von Nordstedt 

 in « Bidr. sydl. Norges Desm.» p. 9 beschrieben. 



E, elegans Bréb. Zygosp. globular, with pretty numerous sim- 

 ple spines, tapering to an acute point. Diam. with sp., Ó4 y., wi- 

 thout sp. 5i,2 y.. — Zyg. sind schon von Ralfs abgebildet. 



