18 R. Gronblod, New Desmids. 



original specimens of Elfving, from which our figures are 

 made. This is not mentioned in the diagnosis by Elfving, 

 which consequently is not quite accurate. Also with regard 

 to another point the diagnosis must be altered. The cell- 

 wall is described as „grosse punctata fere granulata granu- 

 lis majoribus (vel ocellis) circiter 12 plus minus concentrice 

 dispositis", although the cell-wall is not at all granulate, 

 but, on the contrary, delicately punctate (= porose), generally 

 with 11 (sometimes more or fewer) symmetrically arranged 

 scrobiculations. Also West's form (= v. laeve Ducell.) is, 

 I think, nothing else than the typical one. Long. 65, lat. 

 40, crass. 27, isthm. 11 u. [N:o 1092]. 



Hab. Ispois (SW), leg. 0. M. Reuter. PI. 3 fig. 



39—40. 



Genus Micrasterias Ag. 



M. decemdentata (Nag.) Arch.; Nageli, Gatt. einz. 

 Algen. pi. 6 H, fig. 2 (syn. = M. itzigsohnii Braun in Breb., 

 Liste Desm. Normandie pi. 1 f. 2 page 121). The species, 

 as described and figured by more recent authors, does not 

 quite agree with the figure published by Nageli (perhaps 

 better with his description), especially with regard to the 

 shape of the polar lobe. 



M. itzigsohnii Braun 1. c. is not a form of M. 

 truncata, as suggested by West (Alg. Notes V — IX pag. 23 

 fig. 3 A), but seems to be identical with M. decemdentata. 



M. incisa Breb. (syn. Euastr. crux melitensis Ehrbg., 

 Infus. PI. XII quoad fig. Ill c !) most probably belongs to 

 the same species as M. decemdentata. This suggestion is 

 supported by a figure published by Play fair (Plankt. 

 Sydney W. S. pi. 54 f. 31 as „M truncata v. decemdentata 

 X v. incisa, f. mixta"). 



M. neodam ens is Braun 1856 in Rabenh. exsicc. 

 n:o 508 is twice the size of M. decemdentata and it is surely 

 only a form of M. truncata which it resembles with regard 



