Mam·ma·lia /məˈmelɪə/ 名詞 複數
Mam·ma·li·a n. pl. Zool. 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 three 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 mammae.
n : warm-blooded vertebrates characterized by mammary glands in
the female [syn: class Mammalia]