Category:Pleurosigma

Pleu`ro*sig"ma, n. Etym: [nl. See pleuro-, and sigma.] (bot.)

Defn: a genus of diatoms of elongated elliptical shape, but having The sides slightly curved in the form of a letter s. Pleurosigma Angulatum has very fine striations, and is a favorite object for Testing the high powers of microscopes.