6 ASTRID CLEVE, ON RECENT FRESHWATER DIATOMS. 



Var. inlnor Cl. (P. viridis var. minor Cl. in Finl. p. 22). 

 — Cl. Finl. pl. I, 1. 



This variety doubtless belongs to P. streptoraplie, not to 

 P. viridis. 



As typical, I consider tlie forms measuring O, o 7 to 0,0 9 

 mm. in length and liaving 8 to 8,. 5 striae in 0,oi mm., in- 

 terrupted on one side of tlie central nodnle. 



Kv. 1, 32, .Tm. 6, Tr. 38. — Somewhat rare. 



Var. gibbosa A. Cl. n. var. — Pl. I, 1. 



Valve 0,15 to 0,2 mm. in length, 0,02.5 to 0,03 mm. in 

 breadtli, gibbons in tlie middle. Striae 6,5 to 7 in 0,oi mm. 

 sligthly radiate in the middle and tbe ends. Median line 

 strongly complex. 



(11. D. 44. — Rare. 



This form is closely connected witli P. flexnosa Cl. from 

 tbe North American deposits, but is smaller and has closer 

 striae. 



P. major KtJTZ. - A. S. XLII, 8, V. H. v, 3. 



Specimens from Lule Lappmark are about 0,2 mm. in 

 length, 0,0 2 7 mm. in breadth and have 8 striae in 0,oi mm. 

 The striae usnally are 7 in 0,oi mm. (Cl. Finl. p. 24). 



Kv. 1, 9, 26, 34, Nu. 2, 37, Jm. 6, 31, Ks. 15, 20, Km. 10, 

 S.-K. '2-2, Gl. D. 45. — Frequent. 



Var. transversa A. Sm. — A. S. XLIII, 6. 

 Valve 0,14 mm. in length, 0,oi5 in breadth. Striae 9 in 

 0,0 1 mm. 



Nu. 19. — Rare. 



P. Lagerhcimii A. Cl. n. sp. — Pl. I, 2. 



Valve slender, slightly gibbous in the middle, O, le to 0,2 

 mm. in length, 0,oi5 to 0,oi7 mm. in breadtli. Striae 8,5 to 

 9 in 0,01 mm. radiate, alveoli small. Axial area about ^,'3 of 

 the breadth of the valve. Median line strongly complex. 



This species resembles P. major var. transversa A. Sm., 

 but differs from that by the characteristic median line. 



Nu. 5, S.-K. 22, 33. — Rather rare. 



P. Esox. Ehb. — Cl. Finl. pl. I, 3. 



The specimens from Lule Lappmark do not reach the 

 length of 0,14 mm. given by Cleve in Finl. p. 24. They 



