30 Acta Societatis pro Fauna et Flora Fennica. VIIT, n. 2. 



Ab. 36, Sb. 8, 10, 12, 16. 



Foss. Nyl. 87, Sa. 88, Ta. 96, 98, Tb. 90, Ob. 92, Lk. 104. 



P. polyonca Breb. — V. H. Suppl. A, 14. — Nav. mesotyla 

 A. S. XLV, 54, 55. 



Foss. Ta. 94. 



P. globiceps Greg. — V. H. Suppl. A. 13. 



Al. 58 (rare). 



P. intermedia Lgst. — Spitsb. D. I, 3. 



Ab. 36, Lt. 30. 



P. borealis Ehb. — V. H. VI, 3. 



Al. 58, Ab. 36, 49, 54, Nyl. 55, Kon. 40, 41, Sb. 1, 2, 15, 

 Lim. 20, 21, Lt. 29, 33. 



Foss. Ta. 94, 95, 98. 



P. lata Breb. — V. H. VI. 1. 



Nyl. 99. 



P. hungarica Grim. — Verh. 1860, III, 30. — V. H. XI, 23. 

 — Nav. humilis Donk. B. D. X, 7. 



Ab. 46, 47, Kon. 41, Sinb. Ob. 83. 



P. Krookii Grun. — Navicula Krockii Grun. D. Ost. Ung. 

 XXX, 40. 



This species is named in honour of the Swedish botanist 

 Mr. Krook, for which reason the name given by Grunow has been 

 corrected. 



Sinb. Ob. 83 (rare). 



P. undulata Greg. — Micr. J. II, IV, 10, 1859. 



Valve linear, with more or less distinctly triundulate mar- 

 gins, and large, capitate ends. Striae 20 to 22 in 0,oi m. m., 

 almost parallel, convergent at the ends, shortened or interrupted 

 in the middle. Length 0,0 3 to 0,0 3 5 m. m., breadth 0,0 6 m. m. 



Foss. Sa. 88, 89. 



The fig. of Gregory is too small to admit of a trustworthy 

 identification, for which reason I have drawn a new one of the 

 form 1 believe to be the P. undulata, PL II, fig. 8. 



