Plate XLII 



Comparative Series: Lower Jaws of Notharctvs; ]\Iilk Teeth of Nothardns and Ada pis 



1-5. Right ramus of mandibles of Notharctiis from the Bridger Basin, (Middle Eocene), Wyoming. Lateral aspect. Natural size. 



1. A^. osborni, Amer Mus. No. 11466. Lower Bridger. 



2. A'', tenebrosus, Amer. Mus. No. 5009. Lower Bridger. 



3. A^. tenehrosus, U. S. Nat. Mus., No. 3752 (Leidy's type). Lower Bridger. 



4. A'^. pugnax, Amer. Mus. No. 11480. Lower Bridger. ^ 



5. A'^. crassus, Amer. Mus. No. 12588. Upper Bridger. 



6-10. Milk teeth of Adapts and Nolharctus. 



6. Adapin inagnus. PliDsphmiii's of Larnagol (Lot). Right alveolar process with permanent m', three deciduous premolars, 

 alveolus of permanent p^ and deciduous canine. X "f. After Stehlin. 



7. Notharctus tyrannus. Amer. Mus. No. 13025. Middle Eocene, Lower Bridger. Right alveolar process with deciduous pre- 

 molars and two permanent molars in place; p* and m' not erupted. Crown view. X- ( 



8. The same, lingual aspect. X i. 



9. Notharctus tyrannus. Amer. Mus. No. 13029. Lower Bridger. Right ramus of mandible with broken remnants of the decidu- 

 ous premolars, and the three true molars, of which mj is not yet fully in place. The crowns of p4, ps and p2 lie embedded in the jaw. X f • 



10. Notharctus tyrannus. Amer. AIus. No. 12578. Lower Bridger. Right ramus of mandible with mi, m; and alveoli of mi and 

 of the deciduous premolars (molars). The permanent canine is beginning to erupt, and p^ lies embedded in the mandible. X f- 



