Species [ var. orbiculare ]:
33.6-44.8 μm long, 28-39 μm wide, isthmus 7-11 μm wide;
semicells nearly semicircular in side view; cell wall dotted.
[ var. ralfsii W. et G.S. West ]:
31-41 μm long, 22-36 μm wide, isthmus 7-11 μm wide;
semicells close to triangular in side view.
[ var. messikommeri Hirano ]:
21 μm long, 22 μm wide, isthmus 6.5 μm wide;
semicells longitudinally depressed, semicircular or spindle-shaped in side view; bay opened.
[ f. subangulata Messikommer ]:
39 μm long, 29.4 μm wide, isthmus 12.6 μm wide;
semicells conical in side view; bay opened
[ var. depressum Roy et Bisset ]:
19.6-29.4 μm long, 19.6-28 μm wide, isthmus 7-8.4 μm wide;
semicells longitudinally depressed semicircular in side view.
[ var. hibernicum W. et G.S. West ]:
Larger than var. orbiculare,
42-65 μm long, 36-56 μm wide, isthmus 9.5-20 μm wide;
apex of semicells flattened
(Illustrations of The Japanese Fresh-water Algae, 1977).
|