BATS. 7 



propelled in the same manner : it is therefore by a suc- 

 cession of these plunges that their progression on the 

 ground is effected, which is sometimes sufficiently rapid 

 to deserve the name of running. This action, it must be 

 acknowledged, is but a ludicrous attempt compared with 

 the progression of other quadrupeds ; but it is sufficient 

 for their wants. Indeed, the habit of judging of the 

 comparative value and importance of a structure by 

 viewing it only in those forms in which it is most exten- 

 sively developed, is liable to give very erroneous notions 

 of the general adaptation of structure to its function, the 

 contemplation of which constitutes the great charm and 

 interest of all natural science ; and it cannot be too 

 strongly urged, that the apparently imperfect and 

 abortive means of terrestrial progression given to 

 the Bat and the Sloth are as indicative of infinite 

 wisdom as the power of the Lion or the fleetness 

 of the Antelope, because it is equally fitted to their 

 requirements. 



The Bats are all of them nocturnal or crepuscular in 

 their habits. Sleeping during the day in the most re- 

 tired places, some of them in the darkest retreats of 

 forests, in the hollows of trees, suspended from the 

 bark, or concealed amongst the leaves ; others in the 

 most inaccessible parts of ruined edifices, in the roofs 

 of churches, or similar unfrequented places ; they come 

 abroad as soon as the twilight begins to steal over 

 the face of nature, and to offer them the safeguard 

 of obscurity. Then in the pursuit of those insects 

 which, like themselves, avoid the glare of daylight, 

 they exhibit the most rapid and various movements, 

 sometimes flying with great swiftness over the surface 

 of the water, then rising to considerable height in 

 the air, and turning suddenly to one side or the other, 



