Stria density and count in centric diatoms

Centric Total
Image Credit: Loren Bahls
Figure 1. This diatom has a total of 21 striae.
Centric Chord
Image Credit: Loren Bahls
Figure 2. The red line shows a 10 µm chord. It crosses 5 striae, giving a stria count of 5 in 10 µm.