ATAVISMS
Noun
atavisms
plural of atavism
Source: Wiktionary
ATAVISM
At"a*vism, n. Etym: [L. atavus an ancestor, fr. avus a grandfather.]
(a) The recurrence, or a tendency to a recurrence, of the original
type of a species in the progeny of its varieties; resemblance to
remote rather than to near ancestors; reversion to the original form.
(b) (Biol.) The recurrence of any peculiarity or disease of an
ancestor in a subsequent generation, after an intermission for a
generation or two.
Now and then there occur cases of what physiologists call atavism, or
reversion to an ancestral type of character. J. Fiske
Source: Webster’s Unabridged Dictionary 1913 Edition