- 34 - 



3:2. IMunularia sp. tab. nostr., lig. 8. 



L. 0,040 mm., B. U,oi mm. Strice 10 in 0,oi mm. 



Valve rectilinear with rounded apices. Terminal fissm-es conmia- 

 shaped. Apical area narrow. Striae parallel, at right angles to the 

 apical axis, absent in the middle, so that a transapical area arises. 



As I have seen but one specimen of this small form, I dare not 

 regard it as a distinct species. It seems to be nearest to Finn, inacilenta 

 (Ehr.) CI. 



Amphora Ehr. (1840). CI. Syn. II, p. 09. 



o3. A. iU'Utiiisi'ula Ktz. V. H. Syn. tab. 1, fig. 18. 



Solitary in a sample from Lem Dan. 



Area: Greenland, Spitzbergen, Europe, Madeira, New Zealand, Samoa. 



Aclinanthes CI. Syn. II, p. 163. 



Actinoneis CI. 1. c. p. 185. 



34. A. obloDgella Ost. nov. sp. tab. nostr., fig. 9. 



L. 0,057 mm., B. 0,006 nnn. 



Epitheca: apical area narrow, 10 striae in 0,oi mm., finely 

 transversely lineated. Hypotheca: striae very tine, .slightly curved. 

 Central area narrow. 



Hypotheca of this small species highly reminds of Navicula 

 Rokecuia Grun. var. ohloiujella Grun. (V^ H., Syn. tab. XIV, fig. 21). 

 But as I have seen both valves in situ, I am quite sure it is an 

 Aclinanthes. 



Klong Majum. 



In the same sample where Ach. ohloiigella occurs I found a small 

 form, which I have figured in tab. nostr., fig. 10. 



Valve oblong elliptical, L. 0,018 mm., B. 0,007 mm., striae 10 in 

 0,01 mm., somewhat shortened so that an apical area arises. In 

 specimens mounted in styrax it was impossible to see any raphe, 

 but in a dry specimen I could catch a glimpse of a such one with 

 distant central pores. As to the structure of the valve all the .spe- 

 cimens examined were identical. Thus I dare not decide if the 

 present form is an Achnanthes or a Navicula. 



Mkvoneis CI. 1. c. II, p. 187. 



35. A. ininiitissima Ktz. V. H. Syn. tab. XXVII, figs. 37 — 38. 

 Klong Majum, Klong Munse, Lem Dan. (4 samples). 



var. cryptocephala Grun. V. H. I.e. figs. 41— 4i. 



Klong Prao, Klong Munse, Lem Dan. 



Area: the main .species: Greenland, Europa, Mongolia, var. crypfocephala 

 according to Cleve (1. c. p. ISS) Finland. I have found it in the Fa?ro Islands 

 and in Denmark. 



