Defn: A glandular organ for secreting milk, characteristic of all mammals, but usually rudimentary in the male; a mammary gland; a breast; under; bag.
MAMMAL Mam"mal, n.; pl. Mammals. Etym: [L. mammalis belonging to the breast, fr. mamma the breast or pap: cf. F. mammal.] (Zoöl.)
Defn: One of the Mammalia. Age of mammals. See under Age, n., 8.
MAMMALIA
Mam*ma"li*a, n. pl. Etym: [NL., from L. mammalis. See Mammal.]
(Zoöl.)
Defn: The highest class of Vertebrata. The young are nourished for a time by milk, or an analogous fluid, secreted by the mammary glands of the mother.
Note: Mammalia are divided into threes subclasses; —I. Placentalia. This subclass embraces all the higher orders, including man. In these the fetus is attached to the uterus by a placenta. II. Marsupialia. In these no placenta is formed, and the young, which are born at an early state of development, are carried for a time attached to the teats, and usually protected by a marsupial pouch. The opossum, kangaroo, wombat, and koala are examples. III. Monotremata. In this group, which includes the genera Echidna and Ornithorhynchus, the female lays large eggs resembling those of a bird or lizard, and the young, which are hatched like those of birds, are nourished by a watery secretion from the imperfectly developed mammæ.
MAMMALIAN
Mam*ma"li*an, a.
Defn: Of or pertaining to the Mammalia or mammals.
MAMMALIFEROUS
Mam`ma*lif"er*ous, a. Etym: [Mammal + -ferous.] (Geol.)
Defn: Containing mammalian remains; — said of certain strata.