PALEOCENE MAMMALS OF CENTRAL UTAH GAZIN 31 



than the corresponding tooth in E. shepherdi and closely resembles 

 it in form. M2 is considerablj' larger than E. shepherdi and is 

 further characterized by having the talonid basin more restricted 

 anteroposteriorly than was noted in other species. The paraconid 

 is present on M2, though not markedly developed. This cusp seems 

 even less developed on M2 in another referred specimen, No. 15769, 

 in which only this tooth is preserved. 



A few upper teeth may be referred questionably to this species, 

 but these closely resemble upper teeth in E. shepherdi except for a 

 somewhat greater transverse diameter and a more prominent proto- 

 cone. The protocone, however, is not so broad as in M- of Jeps^nia 

 nimitiensis. The reduced extent of the talonid basin of M2 in E. 

 stenxbergi is opposed to the enlargement of the protocone in M^ of 

 J, mantiensis^ although both of these teeth are large relative to 

 other teeth in the series. 



There is no certainty that this form represents the genus Ellipso- 

 don, particularly since the premolars are not known. It is possible 

 that a small species of Mioclaemis is represented. Moreover, the 

 distinctions between E. sternbergi and Jepsenia mantien.sis are not 

 entirely satisfactory, being based for the most part on inference. 



The transverse diameter of the second lower molar in the type 

 is about 5 mm. The anteroposterior and transverse diameters of 

 the third lower molar are 4.4 and 3.3 mm., respectively. 



ELLIPSODON? species (a) 



A lower jaw, U.S.N.M. No. 15781, from the Dragon horizon is 

 unusual in that the two teeth preserved. Mi and M2, have rather 

 blunt cusps, a flattened talonid, and a relatively undepressed area 

 between the three cusps of the moderately elevated trigonid. It 

 resembles somewhat specimens from the Torrejon that have been 

 referred to Ellipsodon inaequidens but with the paraconid more 

 distinctly set off, although this cusp is subdued as are the other 

 cusps of the teeth. This may represent an unusual condition in 

 E. shepherdi but probably represents a distinct form whose affinities 

 are uncertain. 



ELLIPSODON? species (b) 



A small hyopsodont is represented in the Wagonroad horizon by 

 a portion of an upper molar, a second lower molar, and two third 

 lower molars. The upper molar portion, No. 16282, is larger than in 

 ElUpsodon shepherdi and has a relatively more expanded protocone 

 portion, somewhat as in Jepsenia mantiensis but with no evidence of 

 a, hypocone or protostyle although the tooth is noticeably worn. 

 M2, No. 16284, is almost identical in size with this tooth in the 

 type of E. shepherdi but differs from it somewhat in that the tri- 



