Translation 2816

51
2. Cells are oval, elongatëd or pentangular,. 15-30^{ in
length;' apical plates are convex, plane or concave; longitudinal
groove widens distinctly on the hypovaltire. ... P. inconspicuum 2.
3. Cells are ovoid, 18-251.^ in length; the epivalve is
conical, the hypovalve almost hemisFhexiçal P. pusillum'3.
4. Cells are almost spherical, 28-43k in diameter, occasionally
somewhat elongated; apiçal pole is eccentric, apical plates
arranged irregularly. . . . . . . . -. .. . . . . P. centenniale 4,
5, Cells are pentangular, 28-35 M in length, with concave
apical plates; the hypovalve isweakly_ bilobate, with a long, fine
spine on each lobe. . . . . . . . . . . . . . . P. Deflandrei 5.
6. Cells are oval, 3545)Lj in length; antapical plates
are plane or weakly concave; longitudinal groove is very narrow on
the hypovalve; shell is very fragilè and bears little brnamentation.
lubieniense 60
7. Cells are oval, 30--41A in length; plates have arcuate
boundaries; intercalary striation with prominent thickenings, which
are not striated. . . . . . . . . . . . . . . . P. morzinense 7.
8. Cells are pyrifo.rm, 20-28M in length, apical and antrapxcal
plates convex. Ori the border between the antapical plates,
there is a strong, curved spine. .,..... P.► goslaviense B.
9. Cells are pentangular, 25-4W j in length, plates plane
or concave; longitudinal groove isvexy distinctly Videne.d; antapi.c.al
plates always ;,Par
a single, large tooth-like structures or
several somewhat smaller thorns .... P. âfricanum 9.