Marvels of Pond-Life. 67 



place of the limbs of more elaborately-constructed 

 creatures, and give a variety to their means of locomo- 

 tion. The Euplotes is furnished with an oval carapace 

 covering the upper surface, which in different indivi- 

 duals, and probably at different ages, exhibits slightly 

 varied markings round its margin, which in the specimen 

 drawn above consisted of dots. They can run, climb, 

 or swim, and exemplify a singular habit which several 

 of the infusoria possess, that of moving for a little time 

 in one direction, and then suddenly, and without any 

 apparent cause, reversing it. If the reader is fond 

 of learned appellations, he can call this diastrophy, 

 but we do not know that he will be any the wiser 

 for it. 



The Stylonichia are oval animalcules, surrounded by 

 cilia, and having moreover a collection of styles, both 

 straight and curved, the latter called uncini, or little 

 hooks. They swim steadily on, and then dart back, but 

 not so far as they have advanced, and may be seen to 

 keep up this fidgety motion by the hour together. 

 Pritchard tells us Ehrenberg found that a single ani- 

 malcule lived nine days ; during the first twenty-four 

 hours it was developed by transverse self-division into 

 three animals j these in twenty-four hours formed two 

 each in the same manner, so that by self-division only 

 (without ova), these animalcules increased three or four- 

 fold in twenty-four hours, and may thus produce a million 

 from a single animalcule in ten days. Such are the 

 amazing powers of reproduction conferred upon these 

 humble creatures, powers which are fully employed 

 when the surrounding circumstances are favorable, 



