CONTENTS. XIX 



ure — (E) the Pinacoceran type of suture, 350. — Relation of order of 

 succession of initiation to order of ontogenetic development and evo- 

 lutional history — Order of the ontogenetic growth of these characters, 

 352. — Chronological succession of the characters, 353. — Rate of elabo- 

 ration of the various types of suture — Rapidity of modification of each 

 type soon after it was initiated, 354. — Summary of the laws of evolu- 

 tion of the suture-lines of the Ammonoidea, 355. — Evolution of the 

 suture results in the improvement of the structure of the shell, 357. 



CHAPTER XX. 



THE LAWS OF EVOLUTION EMPHASIZED BY STUDY OF THE GEOLOGICAL 

 HIS TORY OF ORGANIS.irS. 



Testimony of vertebrates — Remarkable and extreme evolution of the Mam- 

 mals in the Eocene, 359. — Synthetic types illustrated by Vertebrates of 

 the Mesozoic, 361. — Specialization of five fingers in Reptiles and its 

 relation to later specializations, 362. — ^Finger-bones and teeth as tests 

 of degree of differentiation — Laws derived from the study of the 

 teeth of mammals by Osborne, 363. — Method and purpose in the se- 

 lection of the evidence here set forth — Different kinds of evidence 

 borne by living and fossil organisms, 365 — Natural Selection seems rea- 

 sonable when based alone upon the study of living organisms — Every 

 species of organism that has flourished in the past the fittest for its 

 place and generation, 366. — The geological evidence does not empha- 

 size the importance of natural selection as a factor of evolution, 367. — 

 A statement of the laws of evolution emphasized by fossils, 369. 



CHAPTER XXI. 



PHILOSOPHICAL CONCLUSIONS REGARDING THE CAUSES DETERMINING 

 THE COURSE OF EVOLUTION. 



What is the philosophy of evolution? Statement of the case — The point 

 of view, 371. — The act of evolving as well as the order of events in- 

 cluded in the discussion — The course of the discussion, 372. — Darwin's 

 origin of species centres its interest in the search for causes — The evo- 

 lutional idea of creation, 373.— Evolution the mode of creation of or- 

 ganic beings — The properties of matter not evolved; either eternal 

 or created, 374. — Evolution does not apply to the mode of becoming of 

 chemical or physical properties of matter, but is the distinctive char- 

 acteristic of organisms, 375. — The evolutional idea an enlargement of 

 the conception of God as Creator, 376. — Evolution as an account of the 

 course of the history of creation a gain upon the older idea of arbi- 

 trary creation, but not a satisfactory substitute for creation — Con- 

 sideration of causation indispensable to a thoughtful study of na- 

 ture, 377. — Causes not discovered by observation, but discerned by the 

 reasoning mind, 378. — Ability to adjust the organization to conditions 

 of environment a chief element in the fitness for survival, 379. — The 

 philosophy of evolution: a summary, 3S0. 



