986 THE JOHN DAY FAUNA. 



is smaller than the corresponding tooth of the upper jaw, and much less 



than the same tooth of the known species of Archcelurus and Nimravus. 



Its cusp is obtuse; besides, it has a short cutting heel and an anterior basal 



tubercle. The fourth ]:>remolar is larger, and has an anterior basal cutting 



tubercle, which is shorter than the cutting heel. The sectorial is small for 



the size of the skull, and its cusps are robust. The heel is short and thick, 



and has the peculiarity, entirely unique in the family, of a flat grinding 



surface. 



Measurements of skull. 



■^ M. 



Length from iuiou to iiremaxillary border 280 



Length from inion to chin WO 



Length from premaxillary border to superior canine 019 



Leugtli from premaxillary border to line of orbit 090 



Length from premaxillary bone axially to end of maxillary bone 096 



Length from inion to occipital condyle (horizontal) 048 



Length from inion to postglenoid process 113 



Length from inion to furcation of temporal ridges ll.'j 



Width of zygomata (estimated) 192 



Width of occiput at middle 037 



Width of occiput at condyles 056 



Width of foramen magnum 025 



Width between posttympanic processes 074 



Width of chin at base of symphysis 040 



Length of mandibular ramus 177 



Height of chin medially 050 



Height of chin at flange 048 



Height of ramus at Pm. iii 035 



Height of ramus at M. i 030 



Height of ramus and coronoid process 075 



Length of superior dental series including canine 090 



Long diameter of base of canine 026 



Restoration and liabits. — As the greater part of the skeleton of the Pogo- 

 nodon platycopis is unknown, little can be said as to its general proportions. 

 The skull is one-sixth shorter than that of the usual size of the tiger (Uncia 

 tigris), and is equal to the largest Brazilian variety of the jaguar, and is 

 considerably larger than the Texan form of that species. 



The development of the dentition is concentrated in the canine teeth, 

 and the powers of destniction of the animal would seem to be dispropor- 

 tioned to its ability to appropriate its prey as food. The molar teeth are 

 rather small, as is the case with the earliest representatives of the canine 

 family. The inferior sectorial is primitive and peculiar in its robust heel. 

 We can suppose this species to have been a great destroyer of contemporary 



