A. CLEVE-EULER, DIAT. FLORA OF FINLAND. 7 



Abbreviations of localities, used in the following: 



Ab. — Regio aboensis. Ka. — Karelia australis. 



Ok, — Ostrobottnia kaja- Nyl. — Nylandia. 



nensis. Ob. — Ostrobottnia borealis. 



Sat. — Satakunta. Kk. — Karelia keretina. 



Pennatae. 



Diraphideae. 

 Amphiprora Ehb. 



Amphiprora aboensis n. sp. — PL 1, f. 1. 



Frustule silicious, slightly constricted, 42 jj. in length; 

 half of its breadth 12 a. 



Valve with a rather low keel; junction-line straight. 

 Striation of the keel and valve equal; striae 9 in 10 [i, strong, 

 indistinctly punctate. 



Foss. : Ab. Hindersmossen ^ ; rare. 



As I have seen only a half frustule, the diagnosis must 

 be incomplete. Stil], this species seems well distinguished, 

 especially by the strong striation, from other forms of the 

 genus Amphiprora. 



Tropidoiieis Cl. 



Tropidoneis vitrea (W. Sm.). - V. H. Syn. T. 22, f. 7—9. 

 Foss.: Ab. Hindersmossen. 



Distr. (mar.): North Sea, Atlantic and Pacific coasts of 

 N. America. 



Pleurosigma W. Sm. 



Pleurosigma angulatum Quek. — V. H. Syn. T. 18, f. 1 — 4. 



Foss.: Kk. Knjäsha. 



Distr. (mar.): Arctis; ubiquist. 



^ Though situated in the province of Nyland, this moor geologically 

 belongs to Regio aboensis. 



