WHEEL-BEARERS. 228 



CHAPTER XIV. 



WHEEL-BE ABEBS . 



I MUST now introduce to you a class of animals peculiarly 

 microscopic, since without our marvel- showing instrument 

 they are wholly beyond the sphere of human cognisance. 

 Yet they have been ever since its invention favourite 

 objects with the microscopist ; and I am free to confess 

 that, among all the classes of animated beings, this of the 

 Rotifera * has been my own special delight. Their numer- 

 ous and varied forms, often of remarkable symmetry and 

 elegance, their swiftly-revolving wheels, their vigorous and 

 sprightly motions, their curious habits and instincts, their 

 complete organisation, and the ease and correctness with 

 which this is discerned through their tissues, which have 

 the transparent brilliance of the purest crystal, all com- 

 bine to impart a charm to the Wheel-bearers, which makes 

 the observer hail their appearance in his drops of water 

 with pleasure, and linger over them with unwearied de- 

 light. 



The peculiarity which specially characterises them is 

 the presence of certain organs called cilia, and their 

 arrangement in such a manner that their motion gives to 

 the observer the impression that two toothed wheels are 

 placed on the front of the animal, which are in rapid re- 

 volution on their axes. This was believed to be the real 

 fact by the earlier microscopists, though they were utterly 

 unable to conceive how such a movement could consist 

 with parts maintaining an organic connexion between 



* From the Latin rota, a wheel, and/ero, I bear. 



