The Collaborative International Dictionary of English v.0.48:

Ovist \O"vist\, n. (Zool.)
   A believer in ovism. Same as Ovulist.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ovulist \O"vu*list\, n. (Biol.)
   A believer in the theory (called encasement theory), current
   during the last century, that the egg was the real animal
   germ, and that at the time of fecundation the spermatozoa
   simply gave the impetus which caused the unfolding of the
   egg, in which all generations were inclosed one within the
   other. Also called ovist.
   [1913 Webster]