The Evolution of Organisms 145 



what we must call extinct types or lost races, such 

 as the Graptolites and Trilobites, the Eurypterids 

 and Pterodactyls. It is true that nothing is ever 

 really lost in this economical world. No scien- 

 tific student of what is called the circulation of 

 matter can have failed to recognize the deep truth 

 in the reincarnation of Buddha. The grass be- 

 comes the sheep, the sheep the tiger, the tiger 

 grass again. Atoms that compose part of us may 

 have formed part of a Deinosaur. "The dust of 

 Caesar, dead and turned to clay, may stop a hole 

 to keep the wind away." Yet the physicists' con- 

 solation is wan and cold. The fact remains that 

 those particular combinations of elements which 

 we call lost races those particular smiles of cre- 

 ative genius have disappeared as such forever. 



In most cases, as far as we can judge, the end 

 came slowly, and not by catastrophes. Races 

 waned and died out; they were not suddenly ex- 

 tinguished. Another striking fact is that while 

 evidences of senescence have been detected in some 

 of the last representatives of dwindling races, there 

 are many cases where a full stop seems to have been 

 put to the history of a stock while it was yet in its 

 prime. Nor is there any reason to think of an 

 elimination of weaklings. As Gaudry says : " While 

 insignificant creatures persist, the primes of the 

 animal world vanish without return." The 

 Ammonites ceased at the time of their finest de- 



