Vlll THE TRANSFORMATIONS OF THE ANIMAL WORLD 



PART II 



THE LAWS OF PALEONTOLOGY 

 CHAPTER XIII 



PAGE 



A GLANCE AT THE PROGRESS AND PRESENT STATE OF 



PHILOSOPHICAL PALAEONTOLOGY . . . . 121-24 



BOOK IV 



THE VARIATION OF SPECIES IN SPACE AND TIME 



CHAPTER XIV 



VARIATION IN SPACE AT THE PRESENT EPOCH . ". . 125-38 

 Examples of variation in living species Variation 

 among Land Molluscs : Groups of forms, of varieties, 

 local races, and modes of variation. 



CHAPTER XV 



VARIATION IN SPACE IN GEOLOGICAL TIMES . . . 139-48 

 Examples of variation : The Nassa of Piedmont and 

 the Ammonites of Crussol Regional races at the 

 Cambrian, Liassic, and Pliocene epochs Conclusions. 



CHAPTER XVI 



VARIATION IN TIME . * ."." .* . . 149-66 



Two ways of studying evolution in time Approximate 

 method Method of actual evolution The series of 

 forms or phyletic ramifications Polyphyletic genera 

 Discontinuous series Varying rate of evolution of 

 branches. 



CHAPTER XVII 



PHYLETIC BRANCHES AMONG THE VERTEBRATES . . 167-83 

 Branches of rapid and of slow evolution among 

 the Fishes, Amphibians, and Reptiles Phyletic 

 branches among the Mammals Marsupials and Multi- 

 tuberculata Anthracotherids Proboscidians Con- 

 clusions, i 



