250 POND LIFE. 



tudinally. One bell divides down the middle, with the result that 

 there are now two on the same stalk. By-and-by, however, one of 

 them swims away by means of the cilia, which when the animal is 

 fixed make a whirlpool to catch its food. A stalk then grows like 

 that of the others. This, however, is not the only way in which 

 the Bell-animalcules reproduce their kind ; a bell will detach itself 

 from its stalk and swim about until it comes alongside another. 

 The two melt into one, and form a thick coat round themselves, 

 or in other words become " encysted." The protoplasm in the 

 cyst then breaks up into a number of little portions, each having 

 its own case, and then each of these becomes free and swims about. 

 And now a very curious thing which happens in many of these 

 forms, is that the creature which comes out of this germ where it 

 is free and swimming about, is not a Bell-animalcule, but one of 

 these sucker-bearing animalcules which I described to you just 

 now, and only after another longer or shorter period does the 

 sucker-bearing animalcule encyst itself, and give rise to other 

 germs, which become Bell-animalcules. 



Now, I must pass on to another creature, which bears 



the popular name of the " Slipper-animalcule " {Paramiecmm). 



It has an irregular shape, and does not much resemble a slipper, 



unless it be that of a Chinese lady. It is covered all over with 



cilia, which are very fine and enable it to propel itself through 



the water at a great speed, so that it is almost always roaming 



about, and on that account is difficult to observe. At one end 



there is a funnel which leads into the soft tissue in the centre of 



its body. There is the usual nucleus which we find in all these 



creatures, and within this again is another little body called a 



" nucleolus." Some species have a number of little green specks 



scattered about in the body, which seem to be similar to those 



which impart the green colour to the leaves of plants ; further- 



■ more, it has what looks like two empty spaces, and which are 



called "vacuoles;" they are in reality filled with fluid. One is 



situated at each side of the body, and it has been seen that these 



vacuoles are continually shrinking and expanding again, one 



after the other. In addition to this there has been observed 



(though I do not think any of you are likely to see it), that a 



sort of star-like arrangement projects from the vacuoles just 



