A. CLEVE-EULER, DIAT. FLORA OF FINLAND, 13 



Valve elongated-elliptical, 60 — 120 >^. in length, 40 — 45 ;j. 

 in breadth. Furrows rather narrow, dilated round the central 

 nodule, that is large and a little elongated. Costae 8 — 11 in 

 10 a, alternating with double rows of exceedingly fine puncta. 



Foss.: Kk. Knjäsha, Koudajärvenpää, frequent. Doubt- 

 less marine. 



This large and beautiful form, that has the fine structure 

 of a true DipIoJieis Smithii, recalls as well D. borealis Grun. 

 as D. aestiva Donk., but is distinguished from the former by 

 the much closer furrows and from the latter by the larger 

 central nodule, round which the furrows are bent outwards. 



Diploneis Smithii (Bréb.) var. rhombica n. var. — PI. 1, 

 f. 10. Syn. Navicula Smithii Bréb. A. S. Atl. Tab. 7, f. 18. 



Valve rhombic in outline, 45 a in length, 25 ;j- in breadth. 



Foss.: Ab. Hindersmossen {Litorina-åe^.)\ Sweden. 



This characteristic variety is the one, that usually occurs 

 in Baltic deposits from Litorina-e^yoch. It is not present 

 among the numerous marine species of Diploneis in the 

 Knjäsha-deposit. 



Diploneis borealis (Grun.). Cleve, Syn. Xav. D. I, p. 

 96, non 0strup, Danske D. Tab. 1, f. 17. Sy7i. Navicula 

 Smithii var. borealis f. major Grux. Franz. -Jos. L. D. Tab. 1, 

 f. 40. 



Foss.: Kk. Knjäsha, Koudajärvenpää, not rare. 



Distr. (mar.): Greenland, Arctic Sea, Gullmarefjord. 



Quite t3'pical specimens, perfectly similar to Gruxow's 

 figure. 



Diploneis major Cl. Syn. Xav. D. I, p. 96. — Syn. 

 Navicula Smithii var. V. H. Suppl. PL B, f. 23. 



Foss.: Sat. Panelia; Kk. Knjäsha, Koudajärvenpää, 

 frequent. 



Distr. (mar.): Greenl., Faeroes (0strup), Xorth Sea, 

 Mediterranean, Madagascar, Indian and Pacific Oceans. 



Diploneis major Cl. var. cuneata n. var. — Syn. Navi- 

 cula Smithii Bréb. V. H. Syn. Tab. 9, f. 12. 



Valve elliptical, with parallel margins and broad, cuneate 

 ends. In other respects as the type. 



