A. CLEVE-EÜLER, DIÄT. FLORA OF FINLAND. 51 



f. Striata: 



Central part of the valve with faint, marginal striae as 

 a continuation of the costae. 



Foss.: Kk. Knjäsha, among the type, rare. 



Campylodiscus Thuretii Bréb. — V. H. Syn. Tab. 77, 

 f. 1. — Stjn. Campylodiscus shnulans Greg. A. S. Atl. Tab. 

 17, f. 12—14. 



Foss.: Kk. Knjäsha, Koudajärvenpää, frequent. 



Distr. (mar.): West and East Arctic Sea, North Sea, Asia. 



Campylodiscus noricus Ehb. — V. H. Syn. Tab. 77, f. 

 4— G. A. S. Atl. Tab. 55, f. 8. 



Ladoga. Foss.: Ka. Viborg-dep. (Cleve 1894), Nyl. Kyrk- 

 slätt, Kk. Tuntsa (.4wc^?w5-Sea-dep.); Ok. Paltamo. 



Distr. {fresh lu.); Faeroes (0strup). Europe. Fossil in 

 Baltic deposits from the Ancylus-epoch. 



In the fossil form, the costae reach the centre of the 

 valve and form, where they meet, two lines, crossing each 

 other under right angles, still more distinct than in the fig. 6, 

 quoted above. 



Tropidoraphideae. 



Nitzschia (Hass.) Grun. 



Tryhlionella Grun. 



Nitzschia Tryblionella Hantzsch var. maxima Grun. — 

 V. H. Syn. Tab. 57, f. 11—13. 

 Foss.: Ab. Hindersmossen. 

 Distr. [brack. w.)\ Europe. 



Nitzschia navicularis (Bréb.) Grun. — V. H. Syn. Tab. 

 57, f. 1. 



Foss.: Xyl. Kyrkslätt: Kk. Knjäsha, Niemenkönkään 

 alus (rare, in the uppermost mixed strata). 



Distr. {mar.)\ Europe, Africa, Arctis. Fossil in Baltic 

 deposits from the Litorina-e^iooh, and, rarely, in elder, nor- 

 thern deposits. 



