Gomphonema Ag. (1824), Cl. Syn.I, p. 178. 
8. G parvulum Ktz. V.H. Syn. tab. XXV, fig. 7. 
Klong Sarlakpet. 
var. micropus Ktz. V.H. I. c. figs. 4—5. 
Klong Majum, Lem Dan. 
Area: the main species ubiquitous, var. micropus: Europe, America. 
Obs. In a sample from Lem Dan I found specimens of G. parvulum, 
which are nearest to var. subcapitata (V.H. 1. c. fig. 11), but propor- 
tionately broader. In V. H.'s figure the rate between length and breadth 
is 13:3; in the present form it is 14:5. 
9. G. gracile Ehr. forma major V.H. Syn. tab. XXIV, fig. 12. 
var. naviculoides (W.Sm.) Grun. V.H. l.c. figs. 13—14. 
Klong Prao, Klong Munsé, Klong Son, Koh Samit, Lem Dan. (15 samples.) 
Area: Europe, America, Java, New Zealand. 
10. G. entolejum Ost. sp.nov. tab. nost. fig. 4. 
L. up to 0,065 mm., B. up to 0,01 mm. Strize 10 in 0,01 mm. 
Strie short, marginal. Unilateral stigma present, but hardly 
visible. By its marginal striee and consequently large area this very 
characteristic species reminds of G. Brasiliense Grun. (V. H., Syn. 
tab. XXV, fig. 17) and G. Puiggarianum Grun. (V. H., lL. ¢. fig. 18) 
and perhaps it might be considered an intermediate form between 
those two species, provided they also possessed an unilateral stigma. 
But as this is discernible only with difficulty in G. entolejum, its 
presence in the two mentioned species is still conceivable. 
Klong Prao, Klong Munsé, Klong Majum, Klong Sarlakpet. (5 samples). 
In some of these samples not rare. 
Anomoeoneis Pfitzer (1871) Cl. Syn. II, p. 5. 
its 4 brachysira (Bréb.) Grun. V.H. Syn. tab. XII, figs. 8—9. 
Klong Prao, Klong Son, Klong Munsé, Lem Dan. (9 samples). 
Area: Greenland, Europe. 
12. A. exilis (Ktz.) Gron. V.H. Syn. tab. XI, fig. 11. 
Lem Dan (4 samples). 
Area: Greenland, Europe. 
Navicula Bory (1822). 
Orthostiche Cl. Syn. I, p. 107. 
13. N. euspidata Ktz. var. lanceolata Grun. cnfr. O. Miill. El Kab 
tab. XII, fig. 18; tab. nostr., fig. 2. 
