P. T. Cleve: The Diatoms of Finland. 23 



This form is nearly connected with the var. intermedia and 

 differs only by more close striae, 10 to 11 in 0,oi m. m., more 

 narrow area and smaller size. It measures in length 0,o 7 m. m. 

 and in breadth 0,ou to 0,oi2 m. m. 



Al. 58, Ab. 36, 37, Lad. 86, Sb. 2, 3, 12, 15, Lim. 20, 23. 

 24, Lt. 28, 29, 31, 32, 34. 



Foss. Nyl. 87, Ta. 95, 96, 97, 98, Tb. 90, Lk. 93. 



Var. rupestris Hantzsch — A. S. XLV, 38, 40, 41. 



This form is nearly connected with the var. commutata and 

 has more narrow area and closer striae, about 13 in 0,oi m. m. 



Lim. 21, 26. 



P. streptoraphe CI. n. sp. — Valve linear, with rounded, 

 broad ends, and parallel margins, 0,13 5 to 0,2 m. m. in length 

 and 0,0 2 to 0,0 3 m. m. in breadth. Striae almost parallel or 

 slightly radiant, 5 in 0,oi m. m., crossed by a very distinct band, 

 about one third of the length of the striae. Area narrow. Raphe 

 strongly twisted. 



This species is always easely recognized, and is well figu- 

 red by A. Schmidt (Atl. XLII, 7) and Grunow (Nav. viridis var. 

 sublinearis F. Jos. Land 1,22). — As the name sublinearis already 

 has been given to a Pinnularia (V. H. VI, 25, 26), I think it may 

 be most conveniant to propose a new name, which marks one 

 of the most striking characteristics of the species. 



Pinn. streptoraphe is widely distributed. Swedish localities 

 are Muddes ape and Gellivaara in Lulea Lapmark, Idvattnet in 

 Wilhelmina Lapmark, Sorcelet in Jamtland, Vernamo andForarn 

 (Asnen) in Smaland (all fossil). It occurs also in British deposits 

 from Island of Lewis and in Premney Peat, on Franz Josephs 

 Land (Grun.), in Lac de Grandlieu (Loire inferieur). American 

 localities are: Sing-sing (N. Y.), Salem (Mass.), French pond 

 (Albany), Nova Scotia, Sta Rosa (Gal.). 



Ab. 36, Lim. 21, Lt. 29, 31. 



Foss. B. NyL 102, Ta. 94, 95, Tb. 90, Ob. 92. 

 P. major Ktitz. — V. H. V, 3; A. S. XLII, 8. — P. lepto- 

 gongyla Ehb. p. p. 



This species is distinguished by its narrow centrally inflated 

 valves, about 8 to 10 times longer than broad, 0,2 2 to 0,2 8 m. 

 m. in length and 0,0 2 8 to 0,0 3 m. m. in breadth, its radiate striae, 



