96 



THE VITAL FUNCTIONS. 



situations, and arrangement of the organs of 

 digestion in the Infusoria. They differ also in 

 their degree of compUcation, but without any 

 obvious relation to the magnitude of the ani- 

 malcule. The Monas atomiis, the minutest of 

 the whole tribe, exhibits a nmnber of sacs, 

 opening by as many separate orifices, from a 

 circumscribed part of the surface. In others, as 

 in the Leucophra jxitula, of which Fig. 255 

 represents the appearance under the micro- 



scope, there is a long alimentary canal, tra- 

 versing the greater part of the body, taking 

 several spiral turns, and furnished with a great 

 number of blind pouches, or cceca, as sacs of 

 this description, proceeding laterally from any 

 internal canal, and having no other outlet, are 

 technically termed. These cavities become filled 

 with coloured particles immediately after their 

 entrance into the alimentary canal ; and must 

 therefore be considered as so many stomachs 



