KONGL. SV. VET. AKAPEMIENS IIANnLINaAK. BAND. 18. N:0 5. 9 



9. Navicula Platessa Cl. N. Sp. 



Small, broadly elliptic, with mucronate apices. Striju strong, smooth, 8 in 0,01 

 mm., marginal, leaving around the median line a very large area. 

 Length 0,028 mm. Breadth 0,018 mm. 



PI. I, iig. 12, '"%. 

 Gallapagos Islands rare (Eugenie Exp.). 



This little Navicula belong to the Palpebralis-group, but differs from all de- 

 scribed forms of that section by its short, distant and coarse stri*. 



10. Navicula Haiiekii Cl. N. Sp. 



Very long and slender, linear, somewhat gibbous in the middle and near the 

 ends, convex. Stride punctate, 15 in the middle of the valve, 16 towards the ends and 18 

 in 0,01 mm. in the ends, a little shortened around the central nodule and not reaching 

 the median line, which is surrounded by a linear area. The stria3 are interrupted by 

 a very fine line parallel with the margin. 



Length 0,128 mm. Breadth 0,012 mm. 

 PL II, fig. 27, ^""A. 



Adriatic Sea, Rovigno, stomachs of Holothurians. leg. F. Hauck (rare in Cl. et 

 Moll. Diat. N:o 208210). 



This species seems to belong to the section A^av. liinosai and is allied to N. ma- 

 xima, N. formosa etc. 



11. Navicula Fehigerii Cl. N. Sp. 



Lanceolate, with produced, obtuse ends. Stria? 16 in 0,01 mm., composed of 

 distinct puncta, reaching the median line. In the middle they are alternately longer 

 and shorter around the central nodule, which is surrounded by a broad area. 



Length 0,054 mm. Breadth 0,02 mm. 



PI. II, fig. 21, '""V,. 



Oakland Bridge, California in a sample sent by Mr. Cim. Febiger. 



This beautiful little species has some resemblance to Achnanthes Danica (FlOgel) 

 Grun., but seems to be a true Navicula, belonging to the section punctata3". 



12. Navicula Cluthensis var.? maculifera Cl. 



Broadly oval, with rounded ends. Stria? radiant, reaching the median line, ab- 

 breviated around the central nodule, which is surrounded by a tolerably large area. 

 Number of stria3, (Avhich are composed of distinct puncta), 11 12 in 0,01 mm. 

 Length 0,05 mm. Breadth 0,026 mm. 



PI. II, fig. 23, "7,. 

 Slightly brackish water, near Waxholm, entrance to Stockholm (Mr. Lagerstedt). 

 This form has closer strite than the typical species and an ai^ea around the no- 

 dule. Another smaller foru) is probably. 



2 



K. Sv. Vet-Ak.ad. Hancil. Band. IS. N:o 6. 



