| mammalia | <zoology> 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. Mammalia are divided into three subclasses; I. Placentalia. This subclass embraces all the higher orders, including man. In these the foetus 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. Origin: NL, from L. Mammalis. See Mammal. (20 Mar 1998) |
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| mammalian expression vector | <molecular biology> A vector that will produce large amounts of eukaryotic protein taxonomy notwithstanding, and not necessarily a protein from a mammal. (20 Mar 1998) |