WHEEL-BEAEEK8. 263 



toes, which can be drawn in or extended, widely sepa- 

 rated or brought into contact, at pleasure. By means 

 of these the animal has the power of mooring itself, 

 even to the smooth surface of glass ; and that so fii*mly 

 that from them it can stretch itself in all directions by 

 turns, now and then shaking itself to and fro with sud- 

 den violence, as if irritated, yet without letting go its 

 foot-hold. 



While thus anchored, the action of the ciliary wheels 

 produces considerable whirlpools in the surrounding 

 water, as you will see very distinctly when we have 

 recourse to a curious but simple expedient, first in- 

 vented by Gleichen and since much used by Ehrenberg, 

 of mixing some colouring matter with the water in 

 which the am'mal is. I take a little carmine with a 

 wetted hair-pencil, as if I were going to colour a draw- 

 ing, and allow a small portion of the pigment to diffuse 

 itself in the water which is in the live-box, then, put- 

 ting on the cover, I quickly replace the whole on the 

 stage, and re-find my little Brachion : and now I again 

 submit it to your observation. 



The whole field is now filled with scattered granules 

 of irregular form and size, of a dark-red hue. These 

 are the particles of carmine floating in the water ; par- 

 ticles of alumiaa, that is to say, stained with cochineal. 

 They are in motion, and their movement is more ener- 

 getic the nearer they are to the little animal, which is 

 rotating vigorously in the midst of them. They describe 

 two great circles, concentrical with the two wheels of 

 the Brachionus, and it is easy to see that their rotations 

 are the cause of the movement. The motion of the 

 cilia communicates itself to the surrounding water, and 

 produces circular currents, into which every floating 



