— 130 — 



86. S. undulata Bail. V. H. Syn. tab. XLII, fig. 2. 

 Found only in a sample from K Kt. 



Area: the coasts of N.America, Europe, Red Sea, Ceylon, Hawaii. 



Thalassiothrix Gl. & Gr. 



87. Th. Frauenfeldi Grun. V. H. Syn. tab. XXXVII, figs. 11-12. 

 Only found in a sample from TK. 



Area: Atlantic Ocean, Mediterranean, Red Sea, Indian Ocean, Malay Archi- 

 pelago, China Sea, Pacific Ocean (Ostenfeld). 



Asterionella Hass. 



88. A. notata Gran. V. H. Syn. tab. LII, fig. 3. 

 KKt, s. 1. (3 samples). 



Area: Honduras, Barbadoes, Adriatic. 



Achnanthoideae. 

 Achnanthes Bory. 



89. A. angustata Grev. Gl. Vega Exp. tab. XXXV, fig. 2. 

 KCN, KKt, LN (6 samples). 



Area: Californian guano, Ceylon, Samoa. 

 Occurs sometimes somewhat smaller. 



90. A. brevipes Ag. var. intermedia Ktz. = A. subsessilis Ktz. 

 Perag. Diat. de Fr. tab. I, figs. 19 — 21. 



Found only in a sample from LN. 

 Area: in algis marinis passim (de Toni). 



91. A. javanica Grun. var. rhombica Grun. Tab. nostr. I, figs. 15 & 16. 

 KKt, LN, s.l. (4 samples). 



Area: Java, China, Madagascar. 



As certainly belonging to A. jav. var. rhomb. I refer my fig. 15 

 in shape agreeing with the figure by Petit in Diat. pro v. de Madagascar 

 fig. 8. My fig. 16 (Epitheca) shows two longitudinal lines and a blank 

 spot at each end of the valve on the same side of pseudoraphe. In 

 Achn. Bengalensis Grun. such spots are characteristic according to Gl. 

 Syn. II, p. 196, but here the fact is that „at each end of the valve is a 

 small blank spot on both sides of the area". I have seen a similar valve 

 in connection with a hypotheca showing a conspicuous bifid stauros in 

 the same slide from which my figure is drawn. I suppose that this valve, 

 in spite of the longitudinal lines being remoted from the margin is an 

 epitheca of A. javanica which then possess similar „blank spots", though 



