60 



A HALF-HOUR WITH TUB 



covered over with a piece of thin glass; or they 

 may be placed in the animalcule-cage. They con- 

 sist of a series of cells growing end to end, and 

 their partition- walls can be easily seen. They are 

 of a green colour, from the chlorophyle contained 

 in their interior. In the case of the yoke-threads, 

 the chlorophyle is frequently arranged in a spiral 

 manner along the interior of the filament, as in the 

 -%(/?iem(2 represented at figure 11, plate 1. These 

 yoke-threads may be often seen to unite with each 

 other, and the contents of one cell are emptied into 

 the other, forming the sjjore of the plant, as seen 

 at figure 135, plate 5. The cell contents some- 

 times break up into smaller portions, called 

 zoospores, which, when they escape from the cell in 

 '• which they are contained, move about with great 

 rapidity. This is seen in figure 11, plate 1, at 

 a and b. The moving power of the lower plants 

 is well seen in the division of these confervse, called 

 Oscillator las, which are sometimes found in semi- 

 putrid water. A species is figured at 12, plate 1. 

 As they lie upon the glass slide they will be seen 

 to move over each other in all directions : hence 

 their name. 



Some of the spores formed by the confervse move 

 about by the agency of little organs called cilia. 

 These are extensions of the motile matter of the 

 cell, and are found very commonly in the animal 

 kingdom. Occasionally, a number of these ciliated 

 spores are aggregated together, forming a rapidly- 

 moving sphere. Of this the Pandorina Moruui 

 affords a good example, seen at figure 13, plate 1, 

 in which each spore i:>ossesses two cilia. But the 

 most remarkable of this kind of moving plant is the 

 Volvox glohator, represented in figure 14 of the 

 same plate. This beautiful moving plant was at 

 one time thought to be an animalcule, but it is now 



