ILLUSTRATIONS 



FIGURE PAGE 



II. Primitive amphibian (PalcBogyrinus), Lower 

 Carboniferous. (After Watson.) 



III. Primitive cotylosaurian reptile (Scymouria), 

 Permo-Carboniferous. (After Broili, Williston, Watson.) 



IV. Primitive theromorph reptile (Mycterosaurus), 

 Permo-Carboniferous. (After Williston.) 



V. Gorgonopsian reptile (Scymnognathus), Permian. 

 (After Broom.) 



VI. Primitive cynodont reptile (Ictidopsis), Tri- 

 assic. (After Broom, Haughton.) 



VII. Primitive marsupial (Eodelphis), Upper Creta- 

 ceous. (After Matthew.) 



VIII. Primitive primate (Notharctus), Eocene. 

 (After Gregory.) 



IX. Anthropoid (female chimpanzee). Recent. 



X. Man, Recent. 



49. — Evolution of the Human Skull-roof . 79 



Same series as in Fig. 48, except that in No. VII the 

 recent opossum instead of its fossil ancestor is used. 



Abbreviations: na, nasal; fr, frontal, pa, parietal; 

 it, intertemporal; st, supratemporal; tab, tabular; dso, 

 dermosupraoccipital. 



50. — Evolution of the Human Jawbones . . 80 



Same series as in Fig. 49. 



Abbreviations: pmx, premaxilla; mx, maxilla; dn, 

 dentary. 



51. — Evolution of the Circumorbital Bones . 81 



Same series as in Fig. 49. 



Abbreviations: prf, prefrontal; la, lacrymal; ju, 

 jugal (malar); po, postorbital. 



52. — Evolution of the Bones Behind the Jaws 



(Temporomandibular Series) ... 82 

 Same series as in Fig. 49. 



Abbreviations: sq, squamosal (squamous portion of 

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