The leaf-chinned bat, Mormoops blainvillii, from Maxim's 1912 article. Reproduced from Hughes, H.C. (2000) Sensory Exotica, MIT Press

Cuvier had proposed that bats gained information about obstacles before colliding with them simply by using a heightened sense of touch. The main organ of touch was supposed to be the wing membrane, which certainly is a large area of skin, and is sure to have touch receptors. 19th century biologists imagined the wings to be covered in specialised 'sixth sense' touch receptors, and that the bizarrely shaped faces of some bats were adapted for this same 'touch' reception.

The 'touch' solution to 'Spallanzani's Bat Problem' was given a another scientific examination by the American zoologist Walter Hahn, in 1908.....