Peterson : Miocene Beds of Nebraska and Wyoming. 63 



The fragment (No. 1596) of the left maxillary with P^-, P±, and the 

 molar series, was also collected in the Agate Spring Quarry by Mr. 

 Utterback. The size of the teeth is very nearly as great as that of 

 the specimen which Professors Scott and Osborn described (Bull. Mu- 

 seum Comp. Zool., Vol. XX, p. 100, 1890), but unfortunately the 

 present specimen represents an older individual with teeth too much 

 worn for accurate comparison. As the relative sizes of the teeth 

 agree I judge that the specimens in the Carnegie Museum represent 

 the same species as that which Osborn described. To the observa- 

 tions of the latter author I may add that M^ and ? are of very nearly 

 equal diameters and of nearly the same structure throughout ; they 

 are, respectively, one third greater antero-posteriorly than Mi and are 

 characteristically similar to the teeth of Titanotherhtm as has been 

 stated by others. 



Measurements. 



mm. 



Antero- posterior diameter of P-2- and P± 43 



Antero-posterior diameter of molar series 134 



Antero -posterior diameter of P^ 21 



Transverse diameter of P- 3 - 25 



Antero-posterior diameter of P-4 23 



Transverse diameter of Pi 27 



Antero-posterior diameter of Ml * 36 



Transverse diameter of Mi 30 



Antero-posterior diameter of M^ 54 



• Transverse diameter of M-^ 37 



Antero-posterior diameter of M- 3 - 54 



Transverse diameter of M 1 39 



Merycochoerus ? proprius Leidy. 



From the material at hand there is apparently a wide range of indi- 

 vidual variation in this species. When more material is collected and 

 the different varieties are better known it may be necessary to separate 

 certain specimens (Nos. 1399, 1306, Carnegie Museum Catalogue of 

 Vertebrate Fossils) and give to them a new specific name. For the 

 present the writer thinks it best to give only the principal differences 

 between these and those of the type of Merycochcerus proprius. 



No. 1399 is less robust and differs from the type of Merycochoerus 

 proprius by having a relatively longer maxillary bone, and by having the 

 premolar somewhat wider and longer, measuring antero-posteriorly. 

 A pair of lower jaws, No. 1306 (Carnegie Museum Catalogue of Ver- 



