44 ARKIV FÖR BOTANIK. EAND 14. N:0 9. 



area, with a horseshoe-shaped marginal area on one side of 

 the valve. Striae radiate, fine, about 20 in 10 u.. Hypotheca 

 without areas, 



Foss. : Ab, Hindersmossen {jresh w.). 



This species is distinguished from the preceding variety 

 by the less genuflexed frustules and the much finer striation. 

 It recalls in outline Achn. Peragalli Brun & Hérib., but 

 differs from this species in the lack of central and axial areas. 



Achnanthes brevipes Ag. var. typica Cl. Syn. Nav. D, 

 II, p. 193. — Achnanthes brevipes Ag. V, H, Syn, Tab. 26, f. 

 10—12. 



Foss.: Sat. Panelia (Litorina-dep.). 



Distr. {77iar. and brach, tv.): West and East Arctic Sea, 

 North Sea, Baltic, Caspian Sea. (Foss.) Japan. 



Achnanthes brevipes Ag. var. intermedia Kütz. — Syn. 

 Achnanthes snbsessilis Kütz. V. H. Syn. Tab. 26, f. 25, 28. 



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

 Sea, Baltic, Caspian Sea, Mediterranean Sea, ubiquist. 



Of this variety, quoted already in Cleve's list, I have 

 found specimens in the marine deposit from Knjäsha. An 

 interesting kind of spore has been drawn in PI. 2, f. 53, By 

 contraction of the cell-content and regeneration of the wall, 

 there has been formed a spore in probably about the same 

 way as in Melosira laevis. 



Achnanthes brevipes Ag. var. parvula Kütz. — V. H, 

 Syn. Tab. 26, f. 25, 28. 



Foss.: Kk. Knjäsha, 



Distr. {brack, iv.): Greenland (0strup), North Sea, Cal- 

 vados, Galapagos Islands. 



Achnanthes brevipes Ag. var. forma elliptica 0str. Kyst- 

 diat. Grönl. Tab. 2, f. 13, 



Foss.: Kk. Knjäsha, rare. 



Distr. (mar.): East Greenland. 



Valve of the Finlandian specimens 40 ;j. in length, 18 [x 

 in breadth, with 8 coarsely punctate striae in 10 p.. 



