Part 18

Metazoa. All the complex animals. All the animals except the Protozoa.

Metric system. The decimal system of weights and measures generally used in many countries, employed for many purposes by scientists everywhere. A meter is about 1.094 yards. A kilometer is about .6214 of a mile. A cubic centimeter is about .061 of an inch. A kilogram is about 2.204 pounds. The C. G. S. (centimeter-gram-second) system is used in practically every science which deals with space, mass, and time.

Mho. A unit of electrical conductivity.

Microbe. A very small organism; in popular use, a disease-producing bacterium, a germ.

Micro-. Small, in many compounds.

Mineral. Pertaining to substances which are not organic. An ore.

Mineralogy. The science of ores.

Miocene. Relating to the middle division of the Tertiary (geological) period.

Mitosis. Cell division and multiplication by the usual process.

Mixture. A mass of more than one sort of material which is not chemically compounded or united.

Molecule. The smallest amount of a substance which can exist with the properties belonging to the substance.

Molybdenum. A metallic element. Symbol: Mo.

Momentum. The quantity of motion of a moving body. It is equal to the mass multiplied by the velocity.

Monadelphous. With the stamen filaments in a single bundle.

Moniliform. Jointed in such a way as to resemble a necklace.

Monecious. Hermaphrodite. Having male and female flowers on the same plant.

Monopoly. Sufficient control to influence price.

Monotreme. One of the lowest order (Monotremata) of mammals.

Monsoon. A periodic wind. Specifically, such a wind in the Indian Ocean.

Moraine. The mass of earth and other matter deposited by a glacier.

Morphology. The study of form (of organisms or of words).

Motor. Pertaining to a nerve and an impulse causing motion. Relating to action and the consciousness of action. Pertaining to a muscle causing action. A machine which causes motion, especially such an electric machine or one which is comparatively small.

Muscle. A fibrous band or bundle which contracts to produce movement in an animal body.

Muscology. The study of mosses.

Mutation. A sudden variation which may produce a new species.

Mycology. The study of fungi.

Myriapoda. A class of arthropods including the centipedes.

Narcotic. A substance which induces sleepiness.