P. T. Cleve: The Diatoms of Finland. 37 



This species has not the characters of this section, but 

 seems me nevertheless to be akin to N. Bacillum. 



N. crucicula Donk. — V. H. X, 15. 



Mb. Ab. 100. 



N. subtilissima CI. n. sp. — Valve linear, 0,0 3 2 m. m. in 

 length and 0,005 m. m. in breadth, with capitate ends. Striae 

 very fine and close, about 40 to 45 in 0,oi m. m., stronger, more 

 distant around the central nodule, reaching very nearly to the 

 raphe, slightly radiant, except around the nodule, where they are 

 stronglv radiant. 



PL II, fig. 15. 



Lim. 25. 



The structure of this small species is extremely delicate and 

 it was only with the kind assistance of Prof. Van Heurck I could 

 give the above description. 



N. inflata Donk? — B. D. Ill, 9. 



The fig. in Donk. B. D. is too small and the description too 

 incomplete to admit of a trustworthy identification. The valve is 

 lanceolate with capitate ends, 0,0 2 8 m. m. in length and o,oo?5 

 m. m. in breadth. The striae are radiant in the middle, 19 in 0,oi 

 m. in., convergent at the ends, 22 in 0,oi m. m. and reach the 

 median line, except in the middle of the valve, where they are 

 shortened and alternately longer and shorter. The punctation of 

 the striae is seen only with great difficulty. 



PL II, fig. 2. 



This species is found in the lake Rosslangen (Smaland, Swe- 

 den) and in diatomaceous earth from Houghton (Michigan). 



Sectio: Lim o see. 



N. limosa Kiitz. — V. H. XII, 18, 19, 20. 



Al. 59, Ab. 36, 37, Lad. 86, Sb. 4, Lim. 23, 26, Lt. 31. 



Foss. Ob. 91, Lk. 93, 104. 



Var. ventricosa Donk. — V. H. XII, 24. 



Ab. 36, 48, Kon. 41, Sb. 5, 10. 

 Foss. Ob. 92. 



forma minuta. — V. H. f. 26. 

 Sb. 12. 



