ILLUSTRATIONS 



figure page 



76. — Milk Teeth of Man and Gorilla . . 146 



A. White child. (From Selenka, after Rose.) 



B. Gorilla child. (From Selenka, after Rose.) 



77. — Ten Structural Stages in the Evolution 

 OF the Human Dentition from Ascending 

 Geological Horizons . . . .147 



I. Substage o. Permo-Carboniferous. Myctero- 

 saurus, primitive theromorph reptile. (After Williston.) 

 Substage b. Permian. Scylacosaurus, primitive mam- 

 mal-like reptile. (After Broom.) Substage c. Tri- 

 assic. Cynognathus, advanced mammal-like reptile. 

 (After Seeley.) 



II. Triassic. Diademodon, advanced mammal-like 

 reptile. (Mainly after Seeley. Occlusion diagram by 

 author.) 



III. Jurassic. Pantotherian (primitive pro- 

 placental). (Kindness of Dr. G. G. Simpson. Occlu- 

 sion diagram by Simpson.) 



IV. Cretaceous. Pre-Trituberculate, Deltatheridium. 

 (From the original specimen. Occlusion diagram by 

 author.) 



V. Lower Eocene. Primitive placental, Didel- 

 phodus. (From the original specimen. Occlusion dia- 

 gram by author.) 



78. — Ten Structural Stages in the Evolution 



OF THE Human Dentition (continued) . 148 



VI. Middle Eocene. Primitive primate, Pronycti- 

 cebus. (After Grandidier. Occlusion diagram by 

 author.) 



VII. Upper Eocene. Advanced tarsioid primate, 

 Microchoerus. (After Stehlin. Occlusion diagram by 

 author.) 



VIII. Miocene. Primitive anthropoid primate, 

 Dryopithecus. (Upper molars mainly after Pilgrim; 

 lower molars from type of Dryopithecus cautleyi. Occlu- 

 sion diagram by author and Milo Hellman.) 



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