preformation

The act of shaping or forming in advance; prior formation.

A theory popular in the 1700s that all parts of an organism exist completely formed in the germ cell and develop only by increasing in size.

Antecedent formation; shaping in advance.

An old theory of the preëxistence of germs. Cf. emboîtement.

Prior formation.

The theory that organisms are fully developed in the form of an egg or seed, and just increase in size (as opposed to epigenesis.

a theory (popular in the 18th century and now discredited) that an individual develops by simple enlargement of a tiny fully formed organism (a homunculus) that exists in the germ cell