428 CHAPTERS ON THE NATURAL HISTORY 



animal's body; in the Leaf -nosed bats the external nasal append- 

 ages are simply extraordinary, possessing a wonderful variety 

 of forms and sizes, and of the keenest tactile sense. In fact, 

 anatomically speaking, there is no order of existing mammals 

 presenting a greater number of points of structural or morpho- 

 logical interest than do the representatives of this highly varied 

 group. An entire volume, of goodly size, might with ease be 

 written upon this subject alone. 



In the early days when accounts of animals first came to be 

 written, such naturalists as Pliny classified the bats with the 

 birds, an error committed likewise by one of the authors of the 

 Bible. Even at a much later day, Linmeus included them among 

 the Primates with man and the Apes, chiefly for the reasons that 

 the mammary glands w r ere found upon the fore part of the chest; 

 on account of the number of superior incisor teeth (four in many 

 species); and that the organ of generation in the male was pen- 

 d^nt. Numerous other naturalists, later on, followed suit, as a 

 few similar structures in the organs of reproduction of the fe- 

 male w r ere studied, but all these requirements were subsequently 

 explained by zoologists of more modern date, the position of the 

 mamma?, for example, being evidently related to the position the 

 young must assume during the flight of the mother. As a 

 greater number of species came to be examined with stricter re- 

 gard to anatomical detail, it remained, finally, for Professor Hux- 

 ley to point out that the bats were nothing more nor less than 

 extremely modified Insectivora with their structure almost wholly 

 subservient to the power of flight. " So thoroughly, however, 

 has this adaptation been carried out that," as Sir William Henry 

 Flower says, " of all animals the bats are the least terrestrial, 

 not one of them being equally well fitted, as most birds and in- 

 sects are, for progression on the earth. This is due to the hind as 

 well as the fore-limbs being pressed into the service of aerial lo- 

 comotion. The hind limb is so rotated outwards by the wing- 

 membrane that, contrary to what obtains in all other vertebrates, 

 the knee is directed backwards, and corresponds in position to 

 its serial homologue, the elbow. When placed on the ground, 

 therefore, the animal rests on all fours, having the knees directed 

 upwards like a grasshopper's, while, in order to bring the foot 

 into a position for forward progression, it is rotated forwards 

 and inwards, on the ankle. Walking under these circumstances 

 is at best only a species of shuffle, and that this is fully recog- 



