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Fig. 117.
Po iocystis
Adriatica,
z
PODOCYSTIS. 365
GENUS 75. PODOCYSTIS KUTZ, 1844.
Valves cuneate, furnished with transverse costae
and distinct pseudo-raphe. Frustules cuneate, stipi-
tate, without obvious alae.
Podocystis Adriatica Kutz. (Baa, p. 62; h.v.h. Atl., pi.
55, f. 8*; Type No. 366), fig. 117 above.
Valve cuneate, sometimes attenuate near the base, furnished with trans-
verse costae and rather fine puncta, arranged in transverse and oblique rows.
Marine. Southern shores of England (W. Sm. , Roper), Ireland (O'Meara).
This diatom belongs especially to the Mediterranean and Adriatic.
Euphyllodium spathulatum Shadb. is also a Podocystis,
but it cannot be considered as identical with P. Adriatica, as De Toni and
other authors make it. The valves are furnished with a net work of transverse
and longitudinal costae, anastomosed, thickened ; at the bottom of the cavities
formed by this network is found a transverse costa, excessively delicate, and
bearing on each margin a very minute beard. I therefore assign to this form
the name of
Podocystis spathulatum (Shadb.) H.V.H. The valve
is similar in form to the preceding species. It inhabits the Islands of Ceylon,
Nankoori, etc. It is, perhaps, identical with P. Australica Witt, which I
only know from the description given by De Toni. In the latter case the name
of Shadbolt should be retained, as the species of Witt dates from 1873, while
that of Shadbolt was described in 1854.
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