— 31 — 



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



Valve narrow lanceolate, attenuated towards the apices. Central 

 pores distant. Stripe 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 uino- 

 moeoneis. 



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

 to var. lanceolata. 



Solitai-y in two samples tVoai Klong Prao and Ijeiii Dan. 



Area: Nav. cusp, lane: El Kab. 



14. N. Stodderi Green], var. insigiiis Grun. CI. Syn. l^ tab. Ill, fig. 13. 

 Solitary in two samples from Lem Dan. 



Area: Bengal. 



MesolejcG Gl. Syn. I, p. 127. 



15. N. Pupiila Ktz. V. H. Syn. talx XIII, figs. 15-10. 

 Lem Dan (7 samples). 



Area: ubiquitous. 



Bacillares CI. Syn. I, p. 136. 



16. N. Pseudobacilhim Grun. V. H. Syn. tab. XIII, fig. 9. 

 Sofitary in a sample from Lem Dan. 



Area: Europe, Japan, Australia, New Zealand. 



LineolatcG CI. Syn. II, p. 10. 



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



Lem Dan (3 samples). 

 Area: Europe. 



18. \ radiosa Ktz. var. teneila Breb. V. H. Syn. tab. VII, figs. 21 —22. 

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



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



19. N'. ciiicta Ehr. var. siainensis Ost. var. nov. tab. nostr., fig. 5. 



L. 0,036—0,0') nun., B. 0,ooo— 0,007 mm., strioe 20 in 0,oi mm., 

 finely transversely lineated. 



Valve narrow lanceolate, somewhat attenuated towards the 

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

 towards the apices convergent. Central area narrow. 



Klong Majum, Lem Dan. 



I have considered this form a variant of N. cincta Ehr., allliougli it 

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

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



