XXX ILLUSTRATIONS 



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83. Map — North America in Upper Cretaceous time 206 



84. Convergent forms of aquatic reptiles 207 



85. A plesiosaur from the Jurassic of England 207 



Types of marine pelagic plesiosaurs 20S 



Tylosaurus, a sea lizard 209 



Upper Triassic life of the Connecticut River 211 



Terrestrial evolution of the dinosaurs 211 



Map — North America in Upper Triassic time 212 



A carnivorous dinosaur preying upon a sauropod 213 



Extreme adaptation in the "tyrant" and "ostrich" dinosaurs . . 214 



Four restorations of the "ostrich" dinosaur 215 



Aiicliisaiirus and Platcosauriis compared 216 



Map — the world in Lower Cretaceous time 217 



Map — North America in Lower Cretaceous time 218 



Three principal types of sauropods 219 



Terrestrio-fluviatile theory of the habits of Apatosaiints .... 220 



Primitive iguanodont Camptosaunis 221 



100. Upper Cretaceous iguanodonts from Montana 222 



loi. Adaptive radiation of the iguanodont dinosaurs 223 



102. Tyrannosaurus and Ceratopsia — offensive and defensive energy 



complexes 224 



103. Restoration of the Pterodactyl 226 



104. Ancestral tree of the birds 227 



105. Skeletons of Archccoptcryx and pigeon compared 228 



106. Silhouettes of ArcJicroptcryx and pheasant 22S 



107. Four evolutionary stages in the four-winged bird 22S 



108. Parachute flight of the primitive bird 229 



109. Restoration of Archccoptcryx 229 



no. Reversed aquatic evolution of wing and body form 230 



III. The sei whale, Balcoioptcra boreal is 234 



