CHAPTER IV. 



WHAT IS EOZOON f 



THE- shortest answer to this question is,, that this ancient 

 fossil is the skeleton of a creature belonging to that 

 simple and humbly organized group of animals which 

 are known by the name Protozoa. If we take as a 

 familiar example of these- the gelatinous and microscopic 

 creature found in stagnant ponds, and known as the 

 Amoeba* (fig. 12), it will form a convenient starting 

 point. Viewed under a low power, it appears as a 

 little patch of jelly, irregular in form, and constantly 

 changing its aspect as it moves, by the extension of 

 parts of its body into finger-like processes or pseudo- 

 pods which serve as extempore limbs. When moving 

 on the surface of a slip of glass under the microscope, 

 it seems, as it were, to flow along rather than creep, 

 and its body appears to be of a semi-fluid consistency. 

 It may be taken as an example of the least complex 

 forms of animal life- known to us, and is often; spoken 

 of by naturalists as if it were merely a little particle 

 of living and scarcely organized jelly or protoplasm. 

 When minutely examined, however, it will not be found 

 so simple as it at first sight appears. Its outer layer 

 * The alternating animal, alluding to its change of form. 



