216 



figures 2 a and 2 b (1. c. tab. XIV) have been met with. The first men- 

 tioned form was seen in gatherings from a watercourse near Thorshavn 

 (Str.) and a bog near Trangisvaag (Syd.), the latter form was rather 

 common. 



95. E. crassum (Bréb.) Kiitz. Plate VII, figs. 1 and 1'. 



It is a well-known faet that this species varies very much^ and 

 the specimens from the Færoes also vary considerably in form. 

 They correspond most closely to Lundell's forms (Desm. Suec. p. 17, 

 tab. I, fig. 10 and tab. II, fig. 1) as in front view they are conpara- 

 tively broader than Ralfs's figm'es, and in vertical view are consi- 

 derably thicker, and the deeply undnlating outhne seen in Ralfs's 

 figures is wanting. Both the main form and var. scrobiciilata have 

 been found. With regard to the main form as shown in fig. 1 

 (Plate VII) it was the swellings on the side of the semicells seen 

 from the base which varied, they were sometimes rather sharply 

 marked and sometimes they gradually merged into the sides of the 

 cells. This larger swelling is the middle one of the 3 protuberances 

 seen at the base of the semicells. In the middle of the semicells 

 in front view were two or three slight but — especially when the 

 cells were dry — fairly distinct elevations. The size of the cells 

 was rather small. 



Long. = 135 |M; lat. = 75 |U: crass. = 62|M. 



Var. scrobiculata Lund. Plate VII, fig. 1'. 



Putting aside some less essential differences in the shape of 

 the cells, they correspond fairly well with Lundelfs figures (1. c. 

 tab. II, fig. 1); on the sides of the semicells in front view there 

 were 2 protuberances, and between them, somewhat lower down, 

 a depression. 



Long. = 154: fi; lat. = 80|M; lat. isthm. = 24 fi; crass. — 54 |M. 



The main form was found on Kirkebokamp near Thorsliavn (Str.); 

 Klakken near Klaksvig (Bordo); Skopen and Sand Sand 6); and the 

 variety in gatherings from Klakken (Bordo); and Sand (San do). 



E. magnificnm var. crassioides Hastings^. Dr. O. Nordstedt cailed 

 my attention to this species which must most correctly be considered 

 as a form of E. crassum. 



96. E. oblongum (Grev.) Ralfs. 



The specimens from the Færoes bear a close resemblance to Ralfs's 

 ligures (I. c. tab. XII). The species seems to be rather common as it 

 has been found in many difterent piaces. 



^ See Wildemann: Observations sur quelques Desmidiées. 

 - Hasting: New Desmids from Hampshire in The American monthly 

 microscpical Journal, Vol. 13, 1892. p. 153. 



