DAKOTA AND NEBRASKA. 



51 



Hyreuodon crucians. 



it 

 (I 

 ec 



Length of alveolar border to front of incisors, 

 Depth of lower jaw at coronoid process, 

 " " at last sectorial molar, 



*' " at third premolar, . 



Length of alveolar border of lower jaw, 

 " symphysis of lower jaw, 

 upper molar series, . 

 lower molar series, . 

 upper true molar series, 

 lower true molar series. 



The following are comparative measurements 

 and H. horridus, taken from well preserved and 

 skulls : 



Breadth of first upper premolar. 



Length of " " 



Breadth of second " 



Length of " " 



Breadth of third " 



Length of " " 



Breadth of first upper true molar (obliquely), 



Length of " " " 



Breadth of second " " (obliquely). 



Length of " " " 



Breadth of upper sectorial molar. 



Length of anterior cusp of " 



Length of posterior lobe of " 



Breadth of first lower premolar. 



Length of " " 



Breadth of second " 



Length of " " 



Breadth of third " 



Length of " 



Breadth of fourth " 



Length of " " 



Breadth of first lower true molar, 



Lines. 



Lines. 



Lines. 



Lines 







47 



50 



21 









Hi 







13 



10 





11 



47 



11 







27 



26 



34 



33 



34 



34 



36 





37 



39 



16 



15 



18 



18 



16 







17 



of the teeth of Hycenodon crucians 

 little worn ones contained in two 



H. crucians. 



H. torridus 



Lines. 



Lines. 



. 5 



6i 



. 2i 



3 



. 5 



9i 



. 4 



7J 



. 6 



10* 



. U 



7* 



. 6 



lOi 



. U 



9J 



. 5h 



9 



. 4 



Qi 



. 6 



15 



. 5i 



12 



. 4 



8 



. 5 





. 2 





. 5 



8 



. 3J 



5J 



. 5i 



9J 



. 3i 



7* 



. 5i 



10 



. 4J 



7i 



. 4 



6i 



