ILLUSTRATIONS 



FIGURE PAGE 



60. — Development of Teeth in Lamprey and 



Shark ....... 99 



(After Goodrich.) 



Sections of developing tooth germs: 



A. Lamprey. 



B. Shark. First stage, showing tooth papilla 

 beneath basal layer of epithelium. 



C. Shark. Second stage, showing secretion of 

 the enamel layer. 



D. Shark. Advanced stage, showing lips of 

 shagreen denticles breaking through the epithelium. 



61. — Evolution of the Jaw Muscles from Fish 



TO Man 103 



I. Shark (Chlamydoselache). (Data from Allis.) 



II. Lobe-6nned ganoid (Polypterus). (After L. A. 

 Adams.) 



III. Primitive amphibian (Eryops). Restoration. 

 (After L. A. Adams.) 



IV. Primitive mammal-like reptile (Scymnognathus). 

 Restoration. (Skull mainly from Broom.) 



V. Advanced mammal-like reptile (Cynognathus). 

 Restoration. (After L. A. Adams.) 



VI. Primitive marsupial (Opossum). (After L. A. 

 Adams.) 



VII. Primitive Eocene primate {N otharctus) . 

 Restoration. 



VIII. Chimpanzee. 



IX. Modern man. 



62. — Methods of Attachment of the Primary 



Upper Jaw to the Under Side of the Skull 105 



A. Hyostylic attachment (by means of the hyo- 

 mandibular cartilage), characteristic of shark. (After 

 Gegenbaur.) 



B. Autostylic attachment (by means of an epi- 

 pterygoid process from the primary upper jaw). Car- 



xxvi 



