PALiEOSYOPS. 697 



ridge dividing the external faces of the external cusps. The single inner 

 cusp is connected with the two external by two ridges, which diverge as 

 they extend outwards. The anterior supports a tubercle close within the 

 anterior external. There are strong anterior and posterior basal cingula 

 and weak external and internal ones. 



The third inferior premolar has a compressed ridge on the heel. The 

 fourth premolar is like a true molar, with the anterior inner cusp well devel- 

 oped and elevated, and connected with the anterior and posterior external by 

 oblique ridges. The inner postei'ior cusp is less conic in form than in the 

 true molars, and the entire crown is somewhat contracted anteriorly. Tlie 

 true molars are characterized by the presence of a small median tubercle 

 on the posterior border. There is a low external basal cingulum, which is 

 wanting opposite the posterior cusp. Enamel generally smooth. 



In my original description I stated that there is a diastema in front of 

 the second inferior premolar. This is an error based on a deceptive appear- 

 ance of the jaw. 



Measurements. 



Length of superior true molar series 0210 



Diameters of superior M. a J ^"^'"■''P°«*«"°' ^^^ 



i transverse iM)97 



Diameters of Pm.iv J ''''t«r°P°«t*'"°'' "^^^ 



i transverse 0085 



Length from inferior Pm. iii to M. ii, inclusive 0290 



Diameters of Pm.iv^*°'*^^P°«t«"'"^ — •"°^<' 



transverse 0050 



_. . i. • J. • HI ..(anteroposterior 0075 



Diameters of infenor M. ii ^ '^ 



C transverse 0060 



Depth of ramiis between Pm. iii and Pra. iv 0150 



This species was, to judge from the size of its teeth, about the size of 

 a red fox. The specimens of it above described were found by Mr. J. L. 

 Wortman in the bad lands of the Big-Horn River, Wyoming. It is dedi- 

 cated to my friend, Henry L. Osborne, of Princeton College, New Jersey. 



PAL^OSYOPS Leidy. 



Haydeu's Geological Survey of Montana, 1871, p. 358 (?). Proceedings Academy Natural Sciences, Phila- 

 delphia, 1871, p. 118. Report of the U. S. Geol. Survey of the Territories, I, p. 27, Cope. 

 Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 591. Limnohijus Manh, American Jour- 

 nal Science and Arts, 1872, p. 124. 



This genus has been partially described by Professor Leidy, and much 

 light is thrown on its structure by the materials obtained by the Princetrin 



