524 THE POPULAR SCIENCE MONTHLY. 



natural. The small size of the bats inhabiting this and other parts 

 of the temperate regions of the globe conspires with their nocturnal 

 habits to remove them from general observation, while the great simi- 

 larity one to another of their different species is an obstacle to their 

 popularity even among zoologists since it makes their discrimination 

 and classification a matter of difficulty. 



Yet bats are, as I hope we shall see, really very interesting ani- 

 mals. The bat exhibits to us the body of a beast, specially modified 

 to live the life of a bird, and at the same time serves to give us a fair 

 conception of certain ancient reptilian forms, the remains of which 

 are found deeply buried in deposits made untold ages ago in the 

 secondary rocks. 



But what is a bat? Probably not one of my readers would be 

 likely, if called upon to answer, to fall into the old error of consider- 

 ing it a kind of bird ! 



All who have ever examined a bat closely, and observed its fur, 

 ears, and teeth, must, I think, have recognized it as a kind of beast. 

 Its real affinities, however, serve excellently well to demonstrate how 

 little mere external aspect can be trusted as a guide to fundamental 

 relationship. The bat is essentially an animal of the air all its struct- 

 ure is modified for flight, and it rarely descends to the surface of the 

 ground. The mole, on the contrary, is essentially an animal of the 

 earth all its structure is modified for burrowing, and it rarely ascends 

 to the surface of the ground. The contrast could hardly be more 

 complete, and yet the bat and the mole are cousins the mole, the 

 hedgehog, and the shrew-mouse, belonging to a group of beasts with 

 which the bats show no inconsiderable affinity. 



I have spoken of the opinion that the bat is a kind of bird. This 

 view seems to have been entertained by the Jews, and the " bird of 

 darkness" is placed, in Deuteronomy xiv. 18, among the unclean ones 

 forbidden as food : 



"And the stork and the heron after her kind, and the lapwing and 

 the bat." 



Aristotle, though he placed the bats among flying animals, and 

 therefore among birds, distinctly recognized the differences in their 

 organization ; and the same thing may be affirmed of Pliny. But in 

 spite of this, and although Albertus Magnus, in the middle ages, was 

 fully acquainted with the true nature of bats, as beasts, as well as with 

 their winter torpidity, we find later on a retrogression of opinion. 



Thus Belon, in 1557, in his "Histoire de la Nature des Oyseaux," 

 includes bats with his birds. At the same time, he was not unac- 

 quainted with the mode of their reproduction. 



Yet later by nearly a century in 1645, Aldrovandus decided 

 that bats were rather birds than beasts, and this in spite of his care- 

 ful study of them, as proved by his beginning to distinguish their 

 different kinds one from another. 



