108 ORGANIC MVOLVTION CONSIDERED 



the Primordial. As in the case of the Trilobite, if the 

 Lingula was evolved from some lower form, why did it 

 become fixed when it reached the Primordial aud re- 

 main forever incapable of either change or progress? 

 It certainly cannot be due to uniformity of external 

 conditions — climate and competitors — for they have 

 changed many times. The existence of such long- 

 lived forms as Trilobites, Lingula and the species 

 enumerated, shows inherent incapacity in inorganic 

 beings for undergoing great changes in a state of 

 nature. 



According to the theory of evolution, the summons 

 must have come to Lingula many times to either 

 change its structure or perish — for changing environ- 

 ment is a demand for change of structure; but in 

 spite of all this it still lives and bears witness to the 

 permanence of organic forms. 



If we look at the great class of Brachiopods which 

 have, perhaps, done more to form the limestones than 

 all other animals together, which have existed in all 

 geological ages, we find that while there were many 

 genera and a vast number of species, the representa- 

 tives of the class which are now living are no higher 

 in structure nor do they differ much from those 

 that lived in the earliest geological times. 



Evolution, however, means infinitely more than the 

 derivation of one species of brachiopod from another 

 — it means the derivation of man by descent from 

 some animal that lived in the Primordial. If man is 

 to be thus derived, we must find there some form of 

 life that is extremely and persistently progressive. 



If we examine the Lamellibranchs, the other great 

 class of bivalve mollusks, we find that from the 

 Primordial down to the present time they have under- 

 gone very little change, nor can we say that they have 

 advanced materially in organization. If there has 



