epigenesists

The "epigenesists" held that both the germ and its subsequent organs were built up of juxtaposed molecules according to the operation of a developmental force, or "nisus formations."

The World's Greatest Books — Volume 15 — Science Various 1909

The central point for our purposes is that the 18th century brought debates between metaphysical materialists who were forced into preformationism, and epistemological epigenesists who observed from emerging only gradually and who were willing to accept vitalism as the only apparent causal explanation for the emergence of form from the not-formed [Roe 1981, Maienschein 2000].

Epigenesis and Preformationism Maienschein, Jane 2005

The counter-theory of epigenesis, accepted by Maupertuis, Diderot, and K.F. Wolff, was favorable to transformism because epigenesists re - garded hereditary variations as adding characteristics to living things in the course of their development.

EVOLUTIONISM THOMAS A. GOUDGE 1968