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



Var. elliptica Grim. F. Jos. Land I, 19. — A. S. XLIV, 6, 7. 



Lim. 21. 



Foss. Tb. 90, Lk. 104. 



P. divergens is a most variable species, and seems to gra- 

 duate to P. Legumen. An intermediate form is P. florentina Grun. 

 (A. S. XLIV, 8). 



P. Legumen Ehb. — V. H. VI, 16. — A. S. XLIV, 45, 46. 



Lad. 85. 



Foss. Nyl. 87, Sa. 88, 89, Ta. 94, 95, 98, Tb. 90, Lk. 104. 



P. bicapitata Lagst. — Spitsb. D. I, 5. — A. S. XLV, 69, 70. 



Ab. 36, Sb. 2, Lim. 21, 23, 25, 33. 



Foss. Sa. 88, 89, Ta. 97. 



P. microstauron Ehb. — Stauroptera microstauron Ehb. M. 

 G. XVI, 2, 14. — Stauroneis microstaura Kiitz. Bac. XXIX, 13. — 

 Nav. bicapitata var. subproducta Grun. in V. H. VI, 9. — A. S. 

 XLIV, 14, 34 (typic), 35. — Nav. Brebissonii var. subproducta 

 Grun. in V. H. V, 9. 



Valve linear, with subrostrate ends, 0,0 2 5 to 0,0 8 m. m. in 

 lenght and 0,007 to 0,00 9 m. m. in breadth. Striae divergent, 12 

 in 0,oi m. m., interrupted in the middle of the valve. 



Ab. 36, Sb. 1, 2, Lim. 20, 21, 25, Lt. 30. 



Foss. Sa. 88. 



P. Brebissonii Kiitz. — V. H. V, 7. — A. S. XLIV, 17, 18 

 — P. stauroneiformis W. Sm. B. D. XIX, 178 a. 



Sb. 2, 4, 10, 15, Lt. 30, 32, Lim. 20, 21. 



Foss. Sa. 89. 



Var. diminuta Grun. — V. H. V, 8. 



Sb. 2, 4. 



P. karelica Gl. n. sp. — Valve linear-oblong, four times lon- 

 ger than broad, gradually tapering from the middle to the broad 

 and truncate ends. Striae 15 to 16 in 0,oi m. m., slightly radiant, 

 reaching the raphe, except on the middle, where they are shor- 

 tened and form a large, orbicular area. The end-areas form a 

 straight angle with the raphe and are turned in the same direc- 

 tion. Length of valve 0,0 4 5 to 0,0 5 m. m., breadth 0,on to 0,oi2 

 m. m. 



This small and characteristic species is found in Tana elf 

 (Finmarken), and in the lakes Wenern and Rosslangen (Smaland). 



