Douglass — New Species of Merycocttoerus in Montana. 83 



about the order mentioned. In the last the measurement does 

 not fall short more than half the length of the anterior lobe of 

 m3. The measurements of the first two are taken from 

 Leidy's illustrations.* 



In all of these there is more or less crowding of the first 

 three premolars, and pm 2 is placed obliquely in the jaw. In 

 other respects the mandibles vary so much that we may expect 

 that farther discoveries will show that they do not all belong 

 to the same genus. 



With regard to a first incisor I have no proof that it was 

 possessed by any but M. compressidens. 



* Extinct Mammalian Fauna of Dakota and Nebraska. 



