BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 22. AFD. III. N:0 4. 21 
Nitzschia Acus CL. N. Sp. DLinear, attenuated at the ends. 
Keel very excentric. &L. 0,07; B. 0,002 mm. Puncta 10 in 
0,01 mm., the median distant.: Strize could not be resolved. 
This species, of which I have seen a single specimen 
only, seems to be allied to N. tubicola Grus. — PI. I, 35. 
Nitzsehia aretiea CL. Frustule linear. &L. 0,13; B. 0,014 
mm. with obsoletely plicate connecting zone. Valve narrow 
linear, attenuate to the acute ends. Keel very excentric, its 
puncta 8 in 0,01 mm. a little wider in the middle, where is a 
trace of a central nodule. Strige 25 in 0,01 mm. — P1. I, 21, 22. 
This is the same form as I have found in a gathering 
from Bessels Bay and named N. vitrea var. (Linn. Soc. J. 
Bot! oXX op. 316). 
Nitzschia Brébissonii var. borealis GRUN. Valve in length 
0,14 to 0,17, in breadth 0,006 to 0,008 mm. Keel excentric, 
ftspaneta dt to 3 in 0,01 mm. Strie 17 to 18 in 0.01 mm. 
punctate. — PI. I, 28 to 32. 
To this form, which occurs not rarely on the ice at Cape 
Wankarema, GRUNOW has given the above name (CL. & M. 
Diat. N:o 315—318). OÖeEsTRUP names it N. socialis var. sep- 
tentrionalis (p. 445 P1. VII f. 80). 
Nitzschia diaphana CL. N. Sp. V. slightly sigmoid, linear- 
lanceolate, acute. &L. 0,07; B. 0,006 mm. Keel central. Keel- 
puncta 14 in 0,01 mm., more distant in the middle, where 
there is a distinct central nodule. HStrize 26 in 0,01 mm. — 
BIT 30. 
This form seems, from its central nodule, to belong to 
the group of N. obtusa, and has its nearest relation in N. 
Vidovichii GRUN. 
Nitzschia distans var. erratica. Valve in length 0,18 and 
in breadth 0,01 mm. Keel-puncta 4 in 0,01 mm. Strige about 
SVRmE von. — El 1, 23, 24, 25. 
An exactly similar form occurs not very rarely in the 
Wankarema-material. 
Nitzsehia distans var.? labradoricea CL. Valve in length 0,13 
and in breadth 0,006 mm. Keel-puncta 6 in 0,01 mm. Strize 
about 30 in 0,01 mm. somewhat corroded, for which reason 
the valve seems under certain illumination to be punctate, 
which is also the case with the previous variety. — P1. I, 26, 27. 
Nitzschia hybrida GrUuN. One valve was found exactly 
similar to the variety figured by GRrRuUNow in Franz Josefs 
