ill!Ill

3 82 NITZSCH1A.
H. marina (Donkin) Grun !
(Arct. D., p. 105. Epithemia
marina Donkin ; H.V.H. Atl., pi. 56, f. 14 and 15* ; Type No. 369), plate
15, fig. 489^.
Valve arcuate, with rostrate apices. Keel with 6 dots in 1 c.d.m., prolonged
into delicate costae, which traverse the entire valve, and between each of which
are found two rows of fine alternating puncta. Girdle face linear, showing two
keels inflected towards the connecting zone. Length, about 6 to 10 c.d.m.
Marine. Ostend, Blankenberghe (H.V.H), England (Donkin, Comber, Kitton), France (Br6b),
Ireland (O'Meara).
GENUS 81. NITZSCHIA (HASSALL, 1845; W. SMITH)
GRUNOW Ch. em., 1880.
crr
Fig. 124.
Nitzschia spectabilis.
Valves furnished with a keel, with carinal
dots either short, or prolonged into short
cost;e, rarely traversing the entire valve. Keels
of the two valves diagonally opposite. Frus-
tules free, rarely enclosed in tubes or united
into a stratum.
Endochrome consisting of a single lamina,
interrupted partially or entirely at the median
portion of the frustule.
In the classification of this genus I shall follow
the excellent monograph published by Mr. Grunow
in the Arctische Diatomcen, and I have also
borrowed from him a few of his descriptions.