34 Acta Societatis pro Fauna et Flora Femiica, VIII, n. 2. 



Valve somewhat more than twice as long as broad, with 

 subcapitate-rostrate ends and triundulate margins. Strise 18 in 

 0,oi m. m. composed of distinct puncta, about 24 in 0,0 1 m. m. 

 Length of valve 0,oi5 m. m. Breadth 0,0 6 m. m. 



Sb. 10 (rariss.) 



PI. II, fig. 5. 



This small species is nearly akin to Stauroneis ventricosa 

 (V. H. IV, 1, b), which is no Stauroneis. 



N. tuscula (Ehb.) Grun. — V. H. X, 14. 



Al. 59. 



Foss. Ob. 91, 92, Lk. 93. 



N. lacustris Grun. — Gl. Gr. A. D. pag. 40 ad specim. 

 authent. ! 



This species, which is an inhabitant of fresh water, seems 

 to have been confounded with N. scandinavica Lagst, which is a 

 marine and different species. As no figure of sufficient size is 

 found in the litterature, I have given one PI. II, fig. 14. 



Specimens from Finland are 0,0 4 to 0,0 5 m. m. in length 

 and 0,oi5 m. m. in breadth. The stria? are 14 in 0,oi m. m., 

 somewhat more crowded near the ends. The puncta are distinct, 

 more approximate near the ends, on the average about 18 in 0,oi 

 m. m. The end-fissures are short and seem to be turned in op- 

 posite directions. 



Kon. 41. 



Foss. Ob. 92. 



N. platystoma (Ehb.) CI. — Stauron. plat. Gl. Gr. A. D. Ill, 61. 



Sinb. Ob. 83 (rare). 



N. obliqua Greg. — Stauroneis obliqua M. J. 1856, I, 35, ad 



specim. authent.! 



Valve elliptic, 0,021 to 0,025 m. m. in length and 0,007 to 

 0,oi2 m. m. in breadth. Striae 21 to 24 in 0,oi m. m., composed 

 of crowded, small puncta, forming irregular longitudinal lines. 



PL III, fig. 1. 



Ab. 48, 54, Sinf. 83. 



The fig. of Gregory shows the median line sigmoid, which 



is not exact. 



N. Rotseana Grun. — V. H. XIV, 17. 



Ab. 46, 48, Kon. 41, Sb. 4, 5, 7, Sinb. Ob. 83, Lt. 32. 



