Melita, secondary sexual characters of.
Meloe, difference of colour in the sexes of a species of.
Memnon, young.
Memory, manifestations of, in animals.
Mental characters, difference of, in different races of men.
Mental faculties, diversity of, in the same race of men; inheritance of; variation of, in the same species; similarity of the, in different races of man; of birds.
Mental powers, difference of, in the two sexes in man.
Menura Alberti, song of.
Menura superba, long tails of both sexes of.
Merganser, trachea of the male.