What is a small beaklike process or extension of some part; a small rostrum; as, the rostellum of the stigma of violets, or of the operculum of many mosses; the rostellum on the head of a tapeworm called?

rostellum — A small beaklike process or extension of some part; a small rostrum; as, the rostellum of the stigma of violets, or of the operculum of many mosses; the rostellum on the head of a tapeworm. (Webster's 1913.)