noseleaf

It is probable that the noseleaf, which forms an extended screen stretched behind the nostrils in some of the bats, may be intended by nature to facilitate the collection and conduction of odours, just as the vast expansion of the shell of the ear in the same family is designed to assist in the collection of sounds -- and thus to supplement their vision when in pursuit of prey in the dusk by the superior sensitiveness of the organs of hearing and smell.

Sketches of the Natural History of Ceylon James Emerson Tennent 1836