x ILLUSTRATIONS 



Figure 14. Diagram of the pulse of life Ill 



Figure 15. Squid, Loligo sp., capturing a fish 115 



Figure 16. Fish forms facing page 116 



Figure 17. Laurentian peneplain as seen from the south end of 



Lake Michikamau, Labrador . . . facing page 118 



Figure 18. Lung-fish, Neoceratodus, breathing 121 



Figure 19. African fringe-finned ganoid, Polypterus delhezi . 122 

 Plate III. Cast of the oldest known fossil footprint, Thinopus 

 antiquus, from the Upper Devonian of Pennsylvania 



facing page 124 

 Figure 20. Development of the hind foot of a salamander, 



Triton ttzniatus 124 



Figure 21. Foot of a reptile, Ranodon sibericus 124 



Figure 22. Restoration of the Permian stegocephalian, Cacops 



aspidephorus 125 



Figure 23. Diagram showing the relation of the extra-embryonal 

 membranes: A. bird or reptile, B. mammal 



facing page 128 



Figure 24. Skull of cynodont reptile, Nythosaurus larvatus . . 128 

 Figure 25. Tooth of a carnivorous dinosaur, Allosaurus, and jaw 

 of a contemporary mammal, Diplocynodon 



facing page 132 

 Plate IV. Restoration of archaic mammals: A. Phenacodus pri- 



nKzvus, B. Coryphodon, C. Dinoceras facing page 136 

 Figure 26. Restoration of the creodont, Dromocyon . . . . 135 

 Figure 27. Map showing the geographical distribution of the 

 primates, living and extinct, and their indicated dis- 

 persal from Holarctica 138 



Figure 28. Gorilla, Gorilla gorilla .... facing page 140 

 Figure 29. Gibbon, Hylobates lar facing page 144 



Figure 30. Photograph of a submarine, twenty feet below the 

 surface, taken from the aeroplane whose shadow is 



shown in the picture facing page 144 



Figure 31. Climograph of the northeastern United States . . 159 



Figure 32. Climograph of France and Italy 160 



Figure 33. Climograph of Southern California 161 



