encasement

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

A believer in the doctrine, formerly current, of encasement in the male (see Encasement), in which the seminal thread, or spermatozoid, was considered as the real animal germ, the head being the true animal head and the tail the body.