286 RELICS OF PRIMEVAL LIFE 



Taking, for example, the earliest Protozoa — the 

 Foraminifera and Radiolaria — we find two lines 

 of being that in endless varieties, but with little 

 material change, extend from the earliest periods 

 to the present time. In successive ages they are 

 represented by families, genera, and species, which 

 are regarded as distinct, and known by different 

 names. But these humble animals are very vari- 

 able, and what seem to us to be new types may 

 be merely varieties of ancestral forms. We might 

 even affirm that, for all we know, these two great 

 groups, as they exist in the present ocean, are lineal 

 descendants of those that flourished in the Eozoic. 

 We could not prove this, unless we were to find 

 somewhere a continuous succession of deep-sea de- 

 posits that would show the gradual changes that had 

 occurred. On the other hand, it is hard to believe 

 that one individual life, so to speak, could have con- 

 tinued unimpaired to animate successive and increas- 

 ing masses of matter in all the vast time extending 

 from the Eozoic to the modern. It is also at least 

 equally possible that the causes and conditions, what- 

 ever they were, that produced the earliest Protozoa 

 may have acted again and again in later times, origi- 

 nating new lines of descent with renewed vitality. 



