Apical axis

Apical axis, Longitudinal axis

The axis on the valve face from one apex of the valve to the other; the long axis of a bilaterally symmetric diatom.

References

Hasle, G.R. & Syvertsen, E.E., 1996. Marine Diatoms. In C.R. Tomas (ed), Identifying Marine Diatoms and Dinoflagellates. Academic Press, Inc., California. pp. 5-385.

Dashed line indicates the apical axis