— 155 — 



The longitudinal plication is not of equal height through its whole length 

 but lower near the apices and in the middle so that two lateral elevated 

 spots arise giving this form a very characteristical appearance. The de- 

 cussate striation is only conspicuous on the elevated parts. 



KKt, KCgN, KMn— CLt (3 samples). 



Apiculatœ Grun. 



239. N. margiiiulata Grun. V. H. Syn. tab. LV1II, fig. 13. 

 KKm, KKt (2 samples). 



Area: Kara, Europe, Between Aden and Bab el Mand eb, Malay Archipelago, 

 Borneo, Samoa. 



— — var. didyma Grun. V. H. 1. c. fig. 14. Perag. Diat. de Fr. 

 tab. LXX, fig. 16. 



KKt, KMn KMn -CLt (4 samples). 



The specimens met with have a length of c. 0,04 mm. and are very 

 finely striated; I therefore suppose, that they belong to Grunow's forma 

 minuta (Gl. & Grun. Arct. Diat. p. 73). 



Area: var. didyma: widely distributed. 



forma minuta: Tonga Islands, Samoa, Antilles (Grun o w 1. c). 



Pseudo-Tryblionella Grun. 



240. N. acuta Gl. Gl. West Ind. tab. III, fig. 20. 

 Found only in a sample without habitat. 



Area: Antilles, Tonga Islands, Samoa. 



The present form is a little more rounded at the apices than shown 

 in Cleve's figure. 



241. N. aiata Leud. Fortm. Leud. Fortm. La Mai. tab. II, fig. 11. 

 KKm (2 samples). 



Area: Java. 



Bilobatœ Grun. 



242. N. biiobata W. Sm. var. minor Grun. V. H. Syn. tab. LX, fig. 2. 

 LN (1 sample). 



Area: Brazil, Europe, Society Islands. 



243. N. Jelinecki Grun. Perag. Diat. de Fr. tab. LIX, fig. 19. 

 KKt, s. 1. (2 samples). 



Area: East India, Malay Archipelago. 



In two samples (KKt & s. 1.) I found a Nitzschia, exactly agreeing 

 with N, formica Hantzsch (H. Ost. Archip. tab. VI A, fig. 8). 



In Gl. & Grun. Arc. Diat. p. 74 Grun o w points out that the figure 



