222 



M. R. Thorpe — New Species of 



Crown of P 3 , length of base 11 



Crown of P 3 , maximum width 5 



Crown of P 4 , length of base 21.5 



Crown of P 4 , maximum width 10 



Length of tooth row, P 3 to M t , inc 37 



Diastema, C to P 3 20 



Inferior canine, maximum diameter at alveolus 7 



Inferior canine, transverse diameter at alveolus 4.5 



Crown of P 4 , length of base 12.5 



Crown of P 4 , maximum width 6 



Crown of M 17 length of base 17 



Crown of M 1? maximum width 7.5 



Fig. 5. 



Fig. 5. — Pogonodon cismontaims, n. sp. Left ramus, two-thirds natural 

 size. 



Pogonodon cismontamus, sp. nov. 



(Fig. 5.) 



Holotype, Cat. No. 10053 Y. P. M. White River (Oligocene), Hermosa, 

 South Dakota. 



This specimen, collected by H. F. Wells in 1893, con- 

 sists of a complete left mandibular ramus and the an- 

 terior portion of the right. The left Mj and P 4 are 

 complete. The anterior portion of P 3 is broken away, 

 but the corresponding tooth on the right ramus is com- 

 plete. The left P 2 is missing, but its alveolus is very 

 distinct, while the right P 2 is complete. Hence, consider- 

 ing both rami, there is one complete tooth row from P 2 

 to M 1? inclusive. The tip of the left canine is broken off 

 and, with the exception of I 3 , the incisors are either miss- 

 ing or damaged. 



