24 Acta Societatis pro Fauna et Flora fennica. VIII, n. 2. 



7 in O.oi m. m., traversed by a narrow band, its tolerably large 

 area and the broad, not complex raphe. 



This species occurs generally in larger lakes, as Wenern and 

 Rosslangen (Smaland) in Sweden, Lac Leman in Schwizerland, 

 Lac Gerardmer in the Vosges. 



Lim. 21, Lt. 33. 



Foss. Nyl. 87, Sa. 88, 89, Tb. 90, Ob. 92. 



Var. transversa A. S. — Atl. XLII1, 5, 6 (the striae are in- 

 correctly sketched as punctate). 



This variety is still more slender than the typical specimens, 

 has closer striae, about 8 in 0,oi m. m., and a more oblique, and 

 therefore broader raphe. 



Foss. Lk. 104. 



P. Esox Ehb. — Am, 1, II, 4? — Schum 1, IX, 36. 



This species is distinguished by its triundulated valve, 0,1 4 5 

 m. m. in length and 0,0 2 2 m. m. in breadth. The striae are 9 

 in 0,oi m. m. radiant. The raphe seems not to be complex. 



Foss. Lk. 104. 



PL 1, f. 3. 



P. Dactylus Ehb. — V. H. V, 1 — A. S. XLII, 1, 3, 4. 



This species is easely recognized by its linear-elliptic form, 

 large size (the length being 0,2 2 to 0,3 3 m. m. and the breadth 

 0,0 4 to 0,0 5 m. m.), its coarse striae (5 in 0,oi m. m.) and the 

 broad band crossing them. The raphe is oblique, not complex. 

 The area occupies about the third part of the valve. 



Pinnularia Gigas Ehb. is in no respects, except the large 

 size, different from P. Dactylus. 



Ab. 34, Lt. 32, Lim. 21, 25. 



Foss. Nyl. 87, Ta. 94, 95, Tb. 90, Sa. 88, 89, Ob. 92, Lk. 104. 



P. macilenta Ehb. — M. G. I, 2, 7; 1, 3, 13.? 



I suppose that the name of Ehrenberg may denote this spe- 

 cies, which has the following characteristics: linear, broadly ob- 

 tuse valves, 0,14 to 0,15 m. m. in length and 0,0 2 m. m. in 

 breadth, parallel striae, 8 in 0,oi m. m., crossed by a tolerably 

 broad band, large area and a broad oblique, not complex raphe. 



PL 1, fig. 7. 



This species is found in Sweden in the lake Wenern and in 

 Rosslangen (Smaland). 



