Keel (kēl). The lowest part of the bottom of a ship.

Kettle drum (ket'-l drum). A musical instrument made of a hollow brass hemisphere over which is stretched parchment. This is sounded by blows from a mallet or stick.

Larva (lar'-va); pl. Larvæ (lar'-vē). The young insect.

Lock To fasten in place.

Locust (lō'-kust). A shorthorned grasshopper.

Mantis (man'-tis); pl. Mantes (man'-tēz). (Gr. = prophet.) An orthopterous insect that holds its arms as if in prayer.

Membrane (mem'-brān). (L. membrana = thin skin.) A thin, soft tissue that connects two parts, or lines a body.

Mercaptan (mer-kap'-tan). (L. mercaptans = taking mercury.) A vile-smelling liquid that gets its name because of its strong action on mercury. It seizes upon mercury, so to speak.

Metallic (me-tal'-ik). Made up of metals, or like metals.

Metamorphosis (met-a-mor'-fō-sis). (L. metamorphosis = change, transformation.) A change of form; a development, as the change of the caterpillar into the chrysalis.