48 ARKIV FÖR BOTANIK. BAND 14. N:0 {). 



Surirella tenera Greg, var. subconstricta Hust. Bac. 

 Wümme, p. 312, Tab. 2, f. 6. 



Ladoga. Foss.: Ab. Hindersmossen. 

 Distr. {fresh w.): Germany. 



Surirella distinguenda n. sp. — PI. 3, f. 59. 



Valve heteropolar, lanceolate, with the broader end obtuse 

 and the narrow end attenuated, subacute, frequently slightly 

 curved, as to make the valve somewhat asymmetrical. Wings 

 high and strong, at some distance from the margin, with 10 

 folds in 100 [x. Pseudoraphe visible. Length of the valve 

 70—165 [J., breadth 30—55 [j.. 



Ladoga. Foss.: Ab. Hindersmossen; Ok. Paltamo (/res/iw;.). 



In several fossil gatherings from Fennoscandia, I have 

 remarked this species, that differs from Surirella robusta by 

 the smaller size and more attenuated, frequently not quite 

 symmetrical valves, and moreover is recognised by the strong 

 and sparsely folded wings. Occasionally, it has hitherto 

 been united with Surirella biseriata var. bifrons, from which 

 it, however, must be distinguished as heteropolar. 



Surirella Capronii Breb. — A. S. Atl. Tab. 23, f. 10, 11. 



Foss.: Ab. Hindersmossen, Nyl. Kyrkslätt; in deposits 

 from the Ancylus-epoch. 



Distr. {fresh w.): Germany. Fossil in old Baltic deposits 

 from the Ancylus-^ea.. 



Surirella ovalis Breb. var. Crumena (Bréb.) V. H. — 

 V. H. Syn. Tab. 73, f. 1. 

 Foss.: Sat. Panelia. 

 Distr. {fresh a. brack, w.): Europe, Africa. 



Surirella striatula Turp. var. biplicata Grun. — V. H. 

 Syn. Tab. 72, f. 6. 



Foss.: Ab. Hindersmossen, rare. 

 Distr. {brack, iv.): Europe. 



Surirella striatula Turp. var. denseplicata n. var. 

 Differs from the typical form by the costae being once 

 and a half as close, or 3 7^ in 10 [J.. 



