8 STELLA BURNHAM VINCENT 



animal, Wiedersheim says, they are usually confined to the lips, 

 eyes and cheeks, in other words to the tactile hairs. " Die 

 Tast-oder Spiirhaare sitzen zumeist in der Lippen-, Augen-, und 

 Wangen-gegend, d.h. andern Stellen des Korpers, wo am fruhsten 

 die Behaarung auftritt und von wo sie wahrscheinlich die ver- 

 breitung iiber den ganzen Korper genommen hat."' 



Anatomists and physiologists have studied both the structure 

 and function of the tactile hairs for many years. Zoologists have 

 frequently removed them from different species but have appar- 

 ently been content to note merely the immediate effects of the 

 removal and so far as I know no more extended observations 

 have been undertaken. We are accustomed to think that experi- 

 mentation with animals is confined to recent times and in view 

 of this belief the following incident which Lyddeker gives is 

 interesting : — 



" In their active life, bats being mostly crepuscular or noc- 

 turnal while their eyes are relatively small, it is obvious that 

 they must be provided with some special means of avoiding 

 contact with objects during flight. This appears to be effected 

 by the extreme development of a sense more or less akin to our 

 sense of touch, by which the neighborhood of objects is perceived 

 without actual contact; and it was demonstrated as long ago 

 as 1793, by the cruel experiment of depriving bats of sight and 

 then allowing them to fly in a room across which silken threads 

 were stretched in such a manner as to leave just sufficient space 

 for them to pass with outstretched wings. The unfortunate bats 

 not only succeeded in passing between these threads without 

 contact, and likewise avoided the walls and ceiling of the room, 

 but when the threads were placed still nearer together, they 

 contracted their wings in order to be able to pass without con- 

 tact. — In the great majority of bats it appears that this sense 

 of touch is situated in the wing membranes and in the delicate 

 and frequently enormously elongated ears which are often pro- 

 vided with a kind of secondary inner ear known as the tragus. 

 There are, moreover certain bats provided with an additional 

 organ of perception, which takes the form of expansions of skin 

 from the nose and adjacent parts of the face, foraiing what is 

 generally known as ' nose leaf.' — The various membranes foiTa- 

 ing these nose leaves are always fringed with long fine hairs, 



'Wiedersheim, R.: Vergleichende Anatomic der Wirbelthiere. 1902, S 27. 



