INFUSORIA 463 



to the water, while the animalcules were active, shows the 

 direction of the ciliary motion with great distinctness. 

 The particles form two vortices, one on each side of the 

 front, which meet in the centre in a strong current, and 

 pass off behind the mouth on each side. We do not per- 

 ceive that any of them swallow the particles of carmine, 

 for the internal vessels remain colorless. 



I have found that, if a drop of water containing these 

 animals be placed on a slip of glass exposed to the open 

 air, they do not burst as the water dries away; but dry 

 fiat on the glass, their bodies broader, but shorter than 

 when alive, and quite entire. Their cilia are then very 

 manifest. On being again wetted, though after only a 

 few minutes' desiccation, I have never been able to re- 

 vive them, nor any other Infusoria in like circumstances, 

 notwithstanding what is stated in books. 



Here is another species in equally amazing profusion, 

 jS. mytilus. Its form is oblong, with rounded extremities, 

 the anterior obliquely dilated. This species affords a good 

 example of the various organs of locomotion. A trans- 

 parent oblong shield, which is quite soft and flexible, is 

 spread over the back, which does not prevent the eye dis- 

 cerning all the organs through it, though much more com- 

 monly the animal, when under the microscope, crawls, belly 

 upward, beneath the glass cover of the live-box. Around 

 the anterior part, which is broadened, are placed cilia, 

 which are vibratile ; these are continued round the mouth, 

 a sort of fold on the side. Toward the posterior extremity 

 on each side are other rows of cilia, which being large are 

 well displayed. On the ventral surface, chiefly toward 

 the front part, are seen several thick pointed processes, 

 shaped like the prickles of a rose, but flexible, and capa- 



