BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 20. AFD. III. N:0 2. 15 



Guinardia flaccida. According to H. Peragallo and E. 

 Grove this form was first observed by Stolterforth (T. R. 

 M. S. 1879, p. 835) and named Eucampia sfriata var. maxima. 

 It was afterwards described and fignred by (^astracane 

 (Report on the Diat. coll. by H. M. S. Challenger p. 74, Pl. 

 XXIX, tig. -t) as Bhizosolenia flaccida. As the figure in Castra- 

 cane's work differed in some respects from specimens, found by 

 me in plankton from the Danish archipelago, especially with 

 regard to the annnlation of the connecting zone and the rn- 

 dimentary apicnlns at the margin of the valve, I hesitated to 

 identity them with Gastracane's species and named them Rkizo- 

 ■wlenia? Castracanei. Peragallo, however, considers Rh. flaccidct, 

 and Bh. Castracanei to be identical and has proposed (Mono- 

 graphic" des Rhizosolenias pag. 12, Pl. I, f. 3 to 5) for this and 

 an allied form, the new genus Guinardia, naming this species 

 G. flaccida. — Pl. II, %. 1. 



Lcptocylindrus danicus Cl. (Kanonbaaden Haueks Togter 

 1889, p. 54). — Cellnles cylindrical, with flat (dried, convex) 

 ends, forming Jilaments. Valves without processes or percep- 

 tible strnctnre. — Connecting zone very thin, without annuli 

 — Cell-contents : a few scattered granular chromatophores. 

 Diameter of the filament O.oi m. m. Length of the cellnles 

 0,0 3 to 0.0 6 m. m. 



This pecnliar diatom was originally described from burnt 

 and somewhat misshaped specimens, which led me to describe 

 the valves as convex. In specimens preserved in alcohol they 

 are perfectly plane. — Pl. II, fig. 4, 5. 



