I.] 



MICROSCOPIC PLANTS. 



FIG. 4. 



we shall come across a few instances of movement in 

 the higher plants in the present volume. 



Whilst we have been talking another specimen has 

 come into the field of vision ; and if you are not 

 quick, you will lose a sight of it. It is 

 the Pandorina morum, and it consists of 

 a round cell containing a large number 

 of smaller round cells or spores, each 

 spore provided with two cilia, which pro- 

 trude through the wall of the larger con- 

 taining cell. But I have here, on another slide, a 

 more remarkable and most beautiful form of similar 

 construction. This is the Volvox globator, a species 

 that once puzzled scientific men considerably, to 

 assign the department of nature to which it be- 

 longed. Some considered it was an animalcule, 

 others thought it was a plant, but it has now been 

 satisfactorily settled that it is a plant. It is a most 

 beautiful object under our microscope, as it moves 

 majestically across the field of vision, revolving con- 

 tinually by means of the mul- 

 titude of cilia with which its 

 surface is studded. These cilia 

 are disposed in pairs, as will be 

 seen on reference to the illus- 

 tration, and each pair marks 

 the presence of a cell. These 

 cells are united by very fine 

 threads, and within the sphere 

 thus formed the young Vol- 

 voces revolve. Where found, they are usually in 

 great profusion in fact, the water in some ponds 



FIG. 5. 



