250 DOUGLASS — FOSSIL MAMMALIA 



the lakes are nearly anteroposterior. In the lower teeth also the enamel of the lakes 

 and inner enamel inflections is much lobed. 



I will defer a detailed description of these teeth for a paper which has been partly 

 written, describing several new species of Mylagaulidse and throwing considerable light 



on their development. 



Measurements. 



M. 



From anterior of incisor to posterior of M 3 - "384 



From posterior of incisor to anterior of P 1 021 



Transverse diameter of incisor . , 0032 



Anteroposterior diameter of incisor 0033 



Length of molar-premolar scries 0123 



Length of temporary P- 1 0033 



Width of temporary Pi ° 038 



Length of Mi ° 033 



Width of M- 1 0035 



Length of IP ' 0032 



Width of M» 0034 



Length of M* ° 033 



Width of M* • 0032 



Lowes Jaw. 



Anterior tip of incisor to posterior of M., 033 



Length of molar premolar series 0146 



Length of P, ° 038 



Width of P ¥ 003 



Lengt b Of M T • 003 



Width of M, 004 



Length of M 2 0033 



Width of M 2 ° 04 



Length of M, 0032 



Width of Mi ° 033 



Palmolagus Leidy. 



In the Pipestone beds quite ;i number of jaws and teeth of Palmolagus were found. 

 They apparently belong to three species. One has the third column on the lower 

 molars as in P. triplex. The three portions of mandibles preserved are somewhat smaller 

 than the one described by Cope (1883, p. 881, PI. LXVII, Fig. 28), and may belong- 

 to a different species. 



Several upper and lower jaws I cannot distinguish from /'. lurgidus. 



Palceolagus temnodon, sp. nov. 



There are three series of upper teeth (Nos. 43, 44 and 45) which differ in some 

 respects from previously described species. They vary somewhat in size. P 3 — the first 



