298 ETENINGS AT THE MICROSCOPE. 



the Echinus glide along the side of the tank on its hun- 

 dreds of sucking-disks ! How beautiful, and at the 

 same time how effective, are the ciliary wheels of the 

 BracMonus. 



I am now going to show you some other examples 

 of travelling machinery in an humble and despised, but 

 far from uninteresting class of animals, — the Worms. 

 Here is an Earth-worm upon the garden-border. With 

 what rapidity it winds along, and now it pokes its sharp 

 nose into the ground, and now it has disappeared ! If 

 your eye could follow it, you would see that it makes 

 its way through the compact earth not less easily nor 

 less rapily than it wound along the surface. If you 

 take it into your hand, you perceive no feet, wings, fins, 

 or limbs of any kind ; only this long cylinder of soft 

 flesh, divided into numerous successive rings, and taper- 

 ing to each extremity. The very snout which you saw 

 enter so easily into the substance of the soil, is no hard 

 bony point, but formed of the same soft yielding flesh 

 as the other parts. And yet with no other implement 

 does the little worm penetrate whithersoever it will 

 through the ground. How does it effect this ? 



The fineness of the point to which the muzzle can 

 be drawn is the first essential. This can be so atten- 

 uated that the grains of adherent soil can readily be 

 separated by it, when its action is that of the wedge. 

 The body being drawn into the crevice thus made, the 

 particles are separated still farther. Now another pro- 

 vision comes in ; the whole surface of the skin secretes 

 and throws off a quantity of tenacious mucus or slime, 

 as you will immediately perceive if you handle the 

 Worm ; this has the double effect of causing the pressed 



