P. T. Cleve: The Diatoms of Finland. 27 



0,01 m. m. The area is narrow. Endfissures semicircular. There 

 is on both sides of the central nodule a fissure-like line as in P. 

 stomatophora Grun. 



PL 1, fig. 8, 9. 



Foss. Tb. 90, Ob. 92. 



I found this species in a sample of mud, rich in diatoms 

 dredged from the lake Almten (Misterhult socken, Galmar Ian, 

 Sweden) which was given to me by Mr. Brandel. I have found 

 the same species in a sample from Lac Gerardmer (Vosges) sent 

 to me by mr. P. Petit. 



P. stomatophora Grun. — A. S. XLIV 27, 28, 29. 



Ab. 36, 37, Sa. 75, Sb. 4, 10, Lt. 33, Lim. 20, 21, 23. 



Foss. Nyl. 87, Sa. 89, Ta. 95, Tb. 90, Ob. 92. 



A variety without fissure-like lines on the sides of the central 

 nodule occurs rarely in 36 Ab. 



P. acrosphseria Breb. — A. S. XLIII, 14—17. — Donk. B. D. 

 XII, 2. — Nav. punctata (Arnott) Breb. J. Quek. M. C. 1870, 4. 



Sb. 10, 13. 



P. episcopalis Gl. n. sp. — P. cardinalis Ehb. M. G. XVIII, I, 4. 



Valve large, 6 to 9 times longer than broad, 0,2 3 to 0,3 6 

 m. m. in length and 0,0 3 5 to 0,0 4 m. m. in breadth, linear, with 

 parallel margins and rounded ends. Striae 8 in 0,oi m. m., strongly 

 divergent in the middle and convergent at the ends, interrupted 

 on both sides of the central nodule. Area broad, about one third 

 of the valve. Raphe not complex. 



PL 1, fig. 4. 



This large and beautiful species is akin to P. divergens var. 

 elliptica, but is much larger and more slender, and to Nav. Hart- 

 leyana Grev., but the latter species has gibbous middle and ends. 

 It occurs in Sweden living in Wenern and Rosslangen (Smaland), 

 fossil in the Oja sjo deposit (Blekinge) and in a prseglacial or in- 

 terglacial clay at Hernosand. It is found in Lac Gerardmer (Vos- 

 ges) and in Cherryfield deposit (America). 



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



P. divergens W. Sm. — B. D. XVIII, 177. 



Lad. 86, Sb. 2, 8, 10, Lm. 39, Lt. 29, 31, 33, 34, Lim. 20, 

 21, 23, 24, 26. 



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



