6 VESPERTILIONID^E. 



portant a function. From this view, therefore, it would 

 appear, that "it is by means of the pulsations of the 

 wings on the air that the propinquity of solid bodies is 

 perceived, by the manner in which the air reacts upon 

 their surface." The transverse bands before mentioned as 

 traversing the whole of the flying membrane, are formed 

 of small thickened points, which have very much the 

 appearance of minute glands, particularly on the inter- 

 femoral portion. Have they any connection with the 

 extraordinary sensibility of the membrane just alluded 

 to? 



Similar experiments to these of Spallanzani were 

 made by M. de Jurine, and the details given in the 

 "Journal de Physique" for 1798. The results differed 

 somewhat from those arrived at by Spallanzani ; although, 

 when the eyes were destroyed, the Bats continued to 

 pass and repass through narrow openings with ease, yet 

 M. de Jurine invariably found that, when, in addition 

 to the destruction of the eyes, the auditory openings 

 were effectually closed, the creatures struck their wings 

 against any object which came in their way. 



Although the extremities are adapted, in their most 

 extended action, only for the purposes of flight, yet they 

 are capable of affording the means of walking on the 

 ground, and still more, of climbing with great ease up 

 perpendicular places, if there be sufficient inequalities 

 on the surface to allow of a firm hold by the little 

 hooked nail of the thumb. In walking, the wings are 

 closed, the long fingers being folded against the arm, and 

 the animal rests upon the wrist. The foot of one side is 

 then extended forward, and the thumb-nail is hooked 

 into the ground; the body is next raised by means of 

 the hinder foot, which has been placed partly under the 

 body, and thus thrown forward ; the other side is next 



