— 37 — 



KIong Majum, Klong Munsé. (3 samples). 



With hesitation I regard this form as a variant of E. robusta. It 

 is not identical with E. rob. Papilio, nor with E. Diodou as far as I 

 can jndge. 



49. E. Diodon Ehr. forma minor V. H. Syn. tab. XXXIII, fig. 5. 

 Lem Dan. 



Area: the main species: Europe. 



50. E. lunaris (Ehr.) Grum. var. ? alpina (Nægeli) Grun. V. H. Syn. 

 tab. XXXV, fig. 5. Grun. Banka tab. I, hg. 9. 



Klong Munsé, Klong Son, Koh Samit, Lem Dan. (6 samples.) 

 Area: Europe, India, Java, Banca. 



51. E. Camelus Ehr. genuina Grun. Grun. Banka tab. I, ligs. 6 a 

 and b. 



var. denticulata Grun. Grun. 1. c. fig. 6 d. 



Lem Dan (7 samples). 



Area: Europe, America, Banca. 



52. E. costata Öst. nov. sp. tab. nostr., fig. 14. 



L. up to 0,09 mm., B. up to 0,007 mm., costæ 5 in 0,01 mm. 

 Valve arcuate with parallel dorsal- and ventral margin, terminal 

 nodi on the ventral side, a little removed from the rounded apices. 

 Costæ prominent forming denticuli on the dorsal margin. The 

 frustule rectangular with finely striated connecting zone. 



Klong Prao, Klong Majum, Klong Munsé, Klong Son, Koh Samit, Lem Dan. 

 (8 samples). Not common in any sample. 



Desmogonium Ehr. (1848). Gran. Banka p. 5. 



53. D. Rabenkorstianum Grun. Grun. Banka tab. I, fig. 1. 

 Lem Dan (3 samples). 



Area: China, Banca. 



var crassa Öst. var. nov. tab. nostr., fig. 15. 



L. 0,1 mm., B. 0,008 mm. Striæ 14 — IG in 0,01 mm. Denticuli 

 7—8 in 0,01 mm. 



Naval Station, Lem Dan (3 samples). 



Shorter and broader than the type. Apices somewhat inflated. 



Synedra Ehr. (1831). V. H. Traité p. 307. 



54. S. Ulna (Nitzsch) Ehr. V. H. Syn. tab. XXXVIII, figs. 9, 12 

 and 14. 



Klong Prao, Klong Majum, Klong Munsé, Klong Sarlakpet, Lem Dan. (7 

 samples). 



