242 PROCEEDINGS OF THE NATIONAL MUSEUM vol.83 



Genus ELLiPSODON Scott 



ELLIPSODON AQUILONIUS.^s new species 



Type. — U.S.N.M. no. 9280, right lower jaw with P3-M3 and alveoh. 

 Collected by A. C. Silberling. 



Paratype. — U.S.N.M. no. 9567, right upper jaw wdth P ^-M ^ 

 CoUected by Dr. J. W. Gidley. 



Horizon and locality. — Gidley and Silberling Quarries, Fort Union, 

 Middle Paleocene horizon, Crazy Mountain Field, Mont. 



Diagnosis. — Closest to Ellipsodon acolytus among previously named 

 species. Teeth in general somewhat slenderer in build. Metaconid 

 of P4 more distinct. Talonid of M3 more elongate and narrow. Re- 

 sembles Litaletes in the advancing molarization of P4, but generally 

 nearer to Ellipsodon. Measurements of type in millimeters: 



LITALETES « new genus 



Type.— Litaletes disjundus, new species. 



Distribution. — Middle Paleocene, Fort Union, Mont. 



Diagnosis. — Resembles the most primitive species of Hyopsodus 

 (e. g., H. simplex) in the molarization of T% and presence of a small, 

 distinct hypocone separate from the protocone. Differs in the rela- 

 tively larger M%, rudimentary protocone of P^, smaller hypocones 

 than any typical Hyopsodus, protoconid-metaconid crest less oblique, 

 and paraconid generally less reduced. 



LITALETES DISJUNCTUS.s" new species 



Type.—V.S.'N.M. no. 9323, right lower with C-M3 (M3 broken). 

 Collected by A. C. Silberling. 



Paratype. — U.S.N.M. no. 9324, right upper jaw ^\dth P^-M^ 

 Collected by A. C. Silberling. 



Horizon and locality. — Gidley Quarry, Fort Union, Middle Paleo- 

 cene horizon, Crazy Mountain Field, Mont. 



Diagnosis. — Sole known species of genus. Measurements of type 

 in millimeters: 



*'' Aquilovias, northern. Dr. Gidley recoRnizcd this species, and there is a rough draft of a diagnosis 

 probably of this form, but the diagnosis and designation of type are ambiguous, and as there is no name 

 in his notes or labels ho cannot be quoted as author. 



^'AlxAt, simple +(iX<Tj)r, grinder. From the simple molars and in analogy with Ilaplomylus, Litomylus, 

 and other genera. 



•' Disjundus, disconnected. From its deviation from other members of the family. 



