In birds the term is applied to both jaws with their horny coverings. In quadrupeds the mandible is properly the lower jaw.

MARSUPIALS. — An order of Mammalia in which the young are born in a very incomplete state of development, and carried by the mother, while sucking, in a ventral pouch (marsupium), such as the kangaroos, opossums, etc. (see MAMMALIA).

MAXILLAE. — in insects, the second or lower pair of jaws, which are composed of several joints and furnished with peculiar jointed appendages called palpi, or feelers.

MELANISM. — The opposite of albinism; an undue development of colouring material in the skin and its appendages.

METAMORPHIC ROCKS. — Sedimentary rocks which have