U6 ZOOLOGICAL SKETCHES. 



approach of a little beetle meeting them in their rapid 

 flight? — for that they do not hunt at random, like a 

 whale charging open-mouthed into a shoal of herrings, 

 is proved by their quick turns and dodges in pursuit 

 of an individual insect. Nor can their pygmy eyes 

 help them much. In seizing their prey, the jaws of 

 a bat produce a peculiar clicking sound ; and I have 

 heard that same click at midnight in the deepest gloom 

 of a tropical forest. The long-eared varieties may hear 

 many things that would escape a human ear, but their 

 capacity of finding so much food in the dark is still 

 almost incomprehensible, for most bats are enormous 

 feeders : the Kalong eats twice, and the common horse- 

 shoe bat at least four times, its own weight in the course 

 of the twenty-four hours, and they all have that strange 

 musky odor that seems a characteristic of so many 

 voracious creatures, — the ichneumon, the racing beetle, 

 and the alligator. 



As the Euclidean punctum is defined as a point with- 

 out extension, the voice of a bat might be called a sound 

 without vibrations, — a shrill, sudden squeak, unlike any 

 other sound in nature or art. Though piercing enough 

 to be heard from afar, it is too abrupt to guide the ear 

 in any special direction : you can put a wood-bat in a 

 narrow box, and the box on the table, and bet large odds 

 that the incessant shrieks of the captive will not betray 

 its hiding-place: to nine persons out of ten the sound 

 will seem to come from all parts of the room at once. 



