30 ARKIV FÖR BOTANIK. BAND 14. N.O 9. 



(middle) of the breadth of the valve. Striae almost parallel, 

 slightly convergent at the ends, 10 in 10 a. 



Foss.: Ab, Hindersmossen; Sat. Panelia {jresh w.). 



P. T. Cleve does not distinguish this species, that has 

 the general aspect of Pinnularia paideiisis Grun. (a more 

 closely striate, American species), from P. hemiptera Kütz., 

 probably for the reason that both species have the same 

 number of striae. Nevertheless, they are certainly different, 

 as I could satisfy myself by studying the samples from Hin- 

 dersmossen, where both occur together. The true Pinnvlaria 

 hemiptera is a coarsely built, rather short, linear-cuneate 

 species, sometimes with a more or less visible band across 

 the strong striae, as in the Pinnidariae majores Cl. I have 

 drawn two specimens in PL 1, f. 28, a, b. P. hyhrida has 

 finer striae, though the valves are larger and sometimes reach 

 the remarkable dimensions of 30 X 215 [j.; besides it is more 

 gently tapering from the middle, less cuneate than P. he- 

 miptera. 



In have found in Cleve's manuscripts drawings, evidently 

 representing P. hyhrida, from Rosslängen in Sweden (»P. 

 hemiptera var.?») and from S:ta Flora (»P. instahilis A. Schm.?»). 



Pinnularia nodosa Ehb. f. capitata Cl. Syn. Nav. D. II, 

 p. 87. — Icon. nost. PI. 2, f. 35. 



Foss.: Ab. Hindersmossen. 



Distr. {fresh w.): Sweden, lake Rosslängen (Kalmar län); 

 America. 



As there is no authentic figure of this strongly triundu- 

 late, capitate form, I have drawn it in PI. 2, f. 35. Specimens 

 from Finland often have the area punctate, as stated in Cle- 

 ve's diagnosis. The median inflation is freciuently larger than 

 the two others (as in the var. Formica Ehb., from America). 

 The punctate form comes near to P. acrosphaeria Bréb. 



Pinnularia brevicostata Cl. var. subcapitata n. var. — 

 PI. 2, f. 34. 



Valve linear, with broad, subcapitate, somewhat cuneate 

 ends. Length 63 [j., breadth 10 [J. (middle). Axial area broad, 

 about a third of the breadth of the valve. Central area a 

 transverse fascia. Striae parallel, 10 in 10 p.. 



Foss.: Kk. Niemenkönkään alus, rare {fresh iv.). 



