some Recent Publications concerning Diatoms. 29 



or only faint ones in the central part, and has besides a 

 different outline. 



Navicula musca (p. 61) does not represent Gregory's species, 

 "which is altogether different, but Diploneis didijma^ Ehb. 



Navicula aucklandica (p. Q>^^ : doubtless not Grunow's 

 species ; indeterminable. 



Navicula forcipata, Grev., var. ? (p. 67), seems not to differ 

 from iV. ahrupta, Greg, 



Navicula H (p. 68) is nothing but a form of N. lyra, 

 Ehb. 



Trachyneis velata, A. S., var.? (p. 70). As this species 

 has been noted from the Southern Hemisphere only (Cape 

 of Good Hope, Cape Horn, Ascension), its occurrence in 

 " Kieler Bucht " seems to be very doubtful. Probably 

 T. aspera, var. pulckella. 



Pleurosigma marinum (p. 78) does not represent Donkin's 

 species, which has an altogether ditferent median line. The 

 outline reminds one of P. Normanii, Ralfs, but the central 

 striation and, according to M. Mereschkowsky, the chromato- 

 pliores are different. 



Pleurosigma compactum (p. 86) : probably Gyrosigma 

 arcticum, CI. 



Donkinia baltica (pp. 85, 86) : probably Gyrosigma com- 

 pactum. 



Amphiprora incisa (p. 90) =A. duplex^ Greg. 



Mastogloia Smithii (p. 92). — The right figure does not 

 represent the species of Thwaites, but rather M. lanceolata. 

 The striee are, however, radiate throughout, in which charac- 

 teristic it resembles M. elliptica^ Ag. ; but the median strijB 

 of the latter species are different. 



Cocconeis placentula (p. 94) seems to be a small form of 

 G, scutellum. 



Cocconeis apiculata (p. 94) seems not to agree sufiiciently 

 with A. Schmidt's figure (from Cape of Good Hope). [I 

 have once found in plankton from Skagen a diatom the lower 

 valve of which agreed with fig. 117, but the upper valve was 

 identical with Grunow's Schizostauron Reichardtianum, which 

 thus belongs to Achnauthes, s. 1. Another species, hitherto 

 regarded as a Navicula, viz. Stauroneis obh'qua, has also 



