<prompt> Infundibulum develops from ?Floor of lateral ventricleFloor of 4th ventricleFloor of third ventricleRhombencephalon  <response>: Ans. is c i.e., Floor of third ventricleRef: Textbook of Neuroanatomy p. 112The infundibulum of the diencephalon is a downward evagination of the floor of the third ventricle.As the infundibulum grows down, it meets an ectodermal diveiculum of the oral cavity, known as Rathkes pouch. 