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.

PLEUROSTEON
Pleu*ros"te*on, n.; pl. L. Pleurostea, E. -ons. Etym: [NL., fr. Gr.
(Anat.)

Defn: The antero-lateral piece which articulates the sternum of birds.

PLEUROTHOTONUS
Pleu`ro*thot"o*nus, n. Etym: [NL., fr. Gr. (Med.)

Defn: A species of tetanus, in which the body is curved laterally.
Quain. Dunglison.

PLEUROTOMA
Pleu*rot"o*ma, n.; pl. L. Pleurotomæ, E. Pleurotomas. Etym: [NL., fr.
Gr. (Zoöl.)

Defn: Any marine gastropod belonging to Pleurotoma, and ether allied genera of the family Pleurotmidæ. The species are very numerous, especially in tropical seas. The outer lip has usually a posterior notch or slit.

PLEVIN
Plev"in, n. Etym: [OF. plevine. See Replevin.]

Defn: A warrant or assurance. [Obs.]