A. CLEVE-EULER, DIAT. FLORA OF FINLAND. 29 



Pinnularia rangoonensis CJrun. — Cleve, Syn. Nav. D. 

 II, p. 83. — Icon. nost. PI. 2, f. 30. Syn. Pinnularia sp. 

 A. S. Atl. Tab. 44, f. 26. 



Foss.: Ab. Hindersmossen, Ok. Paltamo, rather frequent. 



Distr. {fresh lo.): Rangoon (?); ubiquist. 



Finlandian specimens are 60 — 70 jj, in length and 9—12 (j- 

 in breadtli. 



In his work Danske Diatoméer 0strup has figured a 

 similar, but larger form, named Pinnularia stauroptera var. 

 linearis. It is 130 \i in length, 17 [j. in breadth, and comes 

 by the shape and semicircular endfissurcs doubtless nearer to 

 P. rangoonensis than to P. stauroptera. Cleve states for the 

 former species a length of 70 — 100 \i. and a breadth of 12 

 —14 |J.. 



Pinnularia rangoonensis Grun. var förarmensis (Grün.). 

 — PI. 2, f. 31. Syn. Pinnularia sp. Å. S. Atl. Tab. 44, f. 28. 

 Navicula deciirrens? A. S. Atl. Tab. 44, f. 29. 



Valve linear, gibbous in the middle, 60 — 75 u- in length, 



9 (ends) to 12 (middle) |j. in breadth, with rounded-subrostrate 

 ends. Axial area V^ — V^ of the breadth of the valve, dilated 

 in the middle to a large, elliptic space. Striae strongly radiate 

 at the middle, convergent at the ends of the valve, 9 — 10 in 



10 [J., the median ones more distant and frequently stronger. 



Foss.: Ab. Hindersmossen, frequent. 



This gibbous form graduates to the preceding, but is very 

 distinct in more inflated specimens. In P. T. Cleve's notes, 

 I have seen an exactly similar figure from Förarm in Små- 

 land, Sweden; I thus suppose that Grunow's Navicula för- 

 armensis denotes this variety, that has not been distinguished 

 from P. rangoonensis in Cleve 's Synopsis. 



Brevistriatae Cl. 



Pinnularia hybrida (Pérag. & Hérib.), Diät. d'Auvergne, 

 p. 85, Tab. 4, f. 9. — Syn. Navicula hemiptera KüTZ. var. 

 Bielawski Hérib. & Perag. 1. c. p. 85, Tab. 4, f. 10. — Icon, 

 nost. PI. 2, f. 32, 33 (f. acuminata). 



Valve linear-lanceolatae, attenuated towards the rounded, 

 obtuse, sometimes subacute ends, 75 — 215 [i. in length, 13 — 

 30 [X in breadth. Area large, lanceolate, a third to a half 



