Defn: Any free-swimming gonophore of a hydroid; a hydroid medusa.
PLANO-CONCAVE
Pla"no-con"cave, a. Etym: [Plano- + concave.]
Defn: Plane or flat on one side, and concave on the other; as, a plano-concave lens. See Lens.
PLANO-CONICAL
Pla"no-con"ic*al, a. Etym: [Plano- + conical.]
Defn: Plane or flat on one side, and conical on the other. Grew.
PLANO-CONVEX
Pla"no-con"vex, a. Etym: [Plano- + convex.]
Defn: Plane or flat on one side, and convex on the other; as, a plano-convex lens. See Convex, and Lens.
PLANOGAMETE
Plan"o*ga*mete`, n. [Gr. wandering + E. gamete.] (Bot.)
Defn: One of the motile ciliated gametes, or zoögametes, found in isogamous plants, as many green algæ (Chlorophyceæ).
PLANO-HORIZONTAL
Pla"no-hor`i*zon"tal, a. Etym: [Plano- + horizontal.]