This term is applied to a peculiar mode of reproduction which prevails among many of the lower animals, in which the egg produces a living form quite different from its parent, but from which the parent-form is reproduced by a process of budding, or by the division of the substance of the first product of the egg.

AMMONITES. — A group of fossil, spiral, chambered shells, allied to the existing pearly Nautilus, but having the partitions between the chambers waved in complicated patterns at their junction with the outer wall of the shell.

ANALOGY. — That resemblance of structures which depends upon similarity of function, as in the wings of insects and birds. Such structures are said to be ANALOGOUS, and to be ANALOGUES of each other.

ANIMALCULE. —