PLATE IX. 



Milk Dentition of Bison americanus. (All the figures natural size.) 



Fig. 1. Right lower pre-molars seen from above, from a very young individual (the first true molar is 



just in sight). Specimen No. 590. 

 Fig. 2. The same seen from the outside. 



Fig. 3. Right upper pre-molars seen from above, from the same specimen. 

 Fig. 4. The same seen from the outside. 

 Fig. 5. Right lower pre-molars, seen from above, from a somewhat older specimen, ill which the first true 



molar is fully in right Specimen No. 1153. 

 Fig. G. The same, seen from the outside. 

 Fig. 7. Rijdit ripper pre-molars, seen from above, from a specimen of about the same age as No. 1153. 



Drawn from specimen No. 1155. 

 Fig. 8. The same, seen from the outside. 



