188 



ON THE EXTINCT MAMMALIA OF 



5. A fragment of the upper jaw, containing the left hinder pair of premolars and 

 the sockets of the first succeeding true molar. The specimen is from an adult of 

 rather advanced age, and is represented in figures 3, 4, plate ix, of the Ancient 

 Fauna of Nebraska. The three teeth mentioned were close together. The separa- 

 tion between the pair of constituent lobes of the crown of the fourth premolar is 

 completely obliterated by wearing, as represented in figure 4 of the plate just 

 mentioned. 



The measurements of the specimen are as follow : 



Lines. 



Width of nose between the frontal angular processes, . . . 12i 



Sjjace occupied by the third and fourth premolars, . . . .24 



6. Anterior extremity of the upper jaw, retaining the greater part of both pre- 

 maxillaries, and containing on both sides the sockets and fangs of the anterior two 

 premolars, the greater part of both canines, and on one side the lateral two incisors 

 and the fang of the inner one. It belonged to an adult, Ijut not an old individual, 

 of more robust proportions than the preceding specimens. It may probably belong 

 to the species hereafter indicated under the name of Entelodon ingens. It is repre- 

 sented as forming the fore part of the muzzle in the restored figure, at d, plate XVI. 



Its measurements are as follow : 



Lines. 



Sjjace included by the anterior two premolars, 



Interval between them, 



Length of crown of canine, . 



Antero-posterior diameter of base of crown, 



Transverse " " 



Antero-posterior diameter of fang of canine at mouth of alveolus, 



Transverse " " " « 



Space between canine and lateral incisor, . 



Space between lateral and second incisor, . 



Length of crown of lateral incisor (Ijlunted), 



Breadth at base of do.. 



Thickness at base of do.. 



Length of crown of second incisor (blunted). 



Breadth at base of do., 



Thickness at base of do.. 



Width of incisive foramina together. 



Breadth of jaw at canine alveoli, 



7. A portion of a cranium of a young individual. 



31 



8 

 24 

 lOJ 



8i 

 13 



9 



8J 



4 

 10 



7 



6 



9 



6J 



13 



44 



