— 31 — 



L. 0,04 mm., B. 0,007 mm. 



Valve narrow lanceolate, attenuated towards the apices. Central 

 pores distant. Striæ fine, at right angles to the apical axis. By 

 slighter enlargement the striation, especially in the central part 

 presents an irregular longitudinal undulation, nearly as in Ano- 

 moeoneis. 



This form probably must be referred to N. cusp.; it is nearest 

 to var. lanceolata. 



Solitary in two samples from Klong Prao and Lem Dan. 

 Area: Nav. cusj). lane: El Kab. 



14. N. Stoddcri Greenl. var. iusignis Grim. GI. Syn. I, tab. III, fig. 13. 

 Solitary in two samples from Lem Dan. 



Area: Bengal. 



Mesolejœ Cl. Syn. ï, p. 127. 



15. N. Pupula Ktz. V. H. Syn. tab. XIII, figs. 15-16. 

 Lem Dan (7 samples). 



Area: ubiquitous. 



Bacillares Cl. Syn. I, p. 136. 



16. N. Pseudobacilliim Grim. V. H. Syn. tab. XIII, fig. 9. 

 Solitary in a sample from Lem Dan. 



Area: Europe, Japan, Australia, New Zealand. 



Lineolatœ Gl. Syn. II, p. 10. 



17. N. cryptocephala Ktz. var. exilis Ktz. V.H. Syn. tab. VIII, fig. 2. 



Lem Dan (3 samples). 

 Area: Europe. 



18. N. radiosa Ktz. var. tenella Bréb. V. H. Syn. tab. VII, figs. 21—22. 

 Klong Majum, Klong Sarlakpet, Lem Dan. (5 samples). 



Area: Greenland, America, Europe, Japan, Tasmania, Australia. 



19. >". cincta Ehr. var. siamensis Öst. var. nov. tab. nostr., fig. 5. 



L. 0,036— 0,05 mm., B. 0,005—0,007 mm., striæ 20 in 0,01 mm., 

 finely transversely lineated. 



Valve narrow lanceolate, somewhat attenuated towards the 

 apices. Striæ in the middle radiate, alternately longer and shorter, 

 towards the apices convergent. Central area narrow. 



Klong Majum, Lem Dan. 



1 have considered this form a variant of N. cincta Ehr., although it 

 differs somewhat in its outline and in its closer striæ. Possibly it is 

 nearer to N. Bottnica Grun. (V. H. Syn. tab. VII, fig. 33). 



