A FEW FACTS ABOUT ZOOLOGY. 15 



similar star-fishes. Then began the study of the fossil 

 animals. 



"And what does this fossil creation tell us? It says this: 

 that in the Silurian Period, taken in its most comprehensive 

 sense, the first in which are found the remains of life, there 

 were the three classes of radiates, the three classes of mol- 

 lusks, two of the elass of art ieulata, and one class of verte- 

 brates — the fishes. In other words, at the dawn of life on 

 earth, the plan of the animal creation with its four funda- 

 mental ideas was laid out; radiates, mollusks, articulates, 

 and vertebrates were present at that first representation of 

 life upon our globe." * Don't misunderstand; don't suppose 

 the same kinds of fishes that now swim in our waters were 

 to be found then; that the same kinds of radiates we now 

 study then adorned the globe. We only mean to state the 

 existence of the four plans, for, though all the types were 

 introduced upon the earth simultaneously, these types have 

 been represented in ever} great geological period by different 

 sets of animals. 



"There is nothing more striking in these early popula- 

 tions than the richness of the types. It would seem as if, 

 before the world was prepared for the manifold existences 

 that now find their home upon the earth, when organic life 

 was limited by the absence of man} T of the conditions that 

 now prevail, the whole wealth of Creative Thought lavished 

 itself upon the forms first introduced upon the globe." After 

 thirty years' study of the fossil crinoids, Agassiz speaks of 

 finding each day some new evidence of the ingenuity, the 

 invention, and the skill shown in varying this single pattern 

 of animal life. 



"These crinoids, or sea-lilies, seem," he tells us, "like the 

 productions of one who handles his work with an infinite 

 ease and delight, taking pleasure in presenting the same 



* Agassiz's " Method of Study of Natural History." 



