Volvocina.] THE INFUSORIA. 119 



from animated beings visible to ordinary vision, that it 

 would be difficult to bring our reason to admit of their 

 vitality, were not their spontaneous motion clearly 

 ascertained; but when examined under a high magnify- 

 ing power, with proper illumination and management, their 

 structure becomes apparent. Figure 39 shews a single 

 free animalcule,, with its two proboscides, and figure 42 a 

 highly magnified view of another,, invested within the lorica. 

 In this figure is seen the disposition of the six cords or 

 tubes which connect it to the surrounding ones ; also 

 numerous corpuscles within the body. A combination of 

 sixteen animalcules (never more, but sometimes less) 

 generally forms the square tablet or plate. 



In order to observe the structure of this highly curious 

 and beautiful creature, considerable adroitness is necessary 

 in the management of the microscope, while a little indigo, 

 conveyed into the water with the point of a camel's hair 

 pencil, will be required to see the whorls and currents set 

 in motion around it. It is almost incredible what power, 

 comparatively speaking, these minute beings possess, 

 notwithstanding the speck they appear to occupy in the 

 scale of creation. The currents are produced by the 

 proboscides, two of which, as we have said, are situated at 

 the mouth of each individual, so that in a tablet or plate, 

 thirty- two, in all twenty-four placed at the edges, and 

 eight standing out from the centre are brought into 

 action. 



The single animalcules (fig. 39) swim like the Monads, 

 in the direction of the longitudinal axis of their bodies, 

 with the mouth foremost, but the plates have a variety of 

 movement : sometimes they move quite horizontally, at 



