FORT UNION OF CRAZY MOUNTAIN FIELD, MONT. 225 



might be a condylarth genus, in which case "it will form a very 

 distinct family of that order." 



Osborn and Earle (1895) placed Mioclaenus in the Condylarthra 

 and proposed a new family Mioclaenidae. They discussed only 

 M. turgidus and evidently intended to include in the family only 

 Mioclaenus and in that genus only the few species not definitely 

 removed by Scott. Matthew (1897) hesitated in regarding the Mio- 

 claenidae as condylarths but did leave them in that group. He placed 

 in the genus Mioclaenus the species Tricenies inaequidens Cope, which 

 Scott (1892) had made type of the genus Ellipsodon, and he proposed 

 a new genus Protoselene for Mioclaenus opisthacus Cope. 



In their 1895 paper, Osborn and Earle described a new genus 

 Oxyacodon, listed as incertae sedis but in the vicinity of the creodonts. 

 Matthew (1897) left the genus as incertae sedis and transferred to it 

 Anisonchus agapefillus Cope. In 1914, in a faunal list, Alatthew 

 transferred Oxyacodon to the Mioclaenidae, with a footnote that it 

 might be a periptj^chid. In his subsequent work (see Pale. Mem.) 

 Matthew confirmed the association of Oxyacodon with Mioclaenus 

 and transferred to it the other Puerco species, ^^Mioclaenus" turgi- 

 dunculus, thus confining the genus Mioclaenus {sensu stricto) to the 

 Middle Paleocene. He also revived Ellipsodon Scott and placed in 

 it Mioclaenus acolytus Cope and Mioclaenus lemuroides Matthew. 



The arrangement reached b}^ Matthew is thus as follows: 



p „ , jType: 0. apiculatus. 



[Referred: 0. agapetillus, O. tiirgiduncvhis, 0. ■priscilla. 

 ,,. , [Type: M. turgidus. 



Torre j on ' 



p,,, . , jType:S. inaequidens. 



[Referred: E. lemuroides, E. acolytus. 

 Protoselene: Type: P. opisthacus. 



The history of the Eocene group Hyopsodontidae has been suffi- 

 ciently noticed in connection with the discussion of the Condylarthra 

 as whole. Matthew early recognized that the hyopsodontids and 

 mioclaenids were related and in 1909 suggested that future discovery 

 might result in merging the two supposed families. In his Paleocene 

 memoir he toolc this step, retaining the earlier double grouping in the 

 form of two subfamilies, Hyopsodontinae with Haplomylus and 

 Hyopsodus and Mioclaeninae with the earlier genera listed above. 



After Matthew's work numerous discoveries of new hyopsodontids 

 have been made. Jepsen (1930) described Litolesies and Phena- 

 codaptes from the Upper Paleocene of Wyoming. He placed the 

 former doubtfullj'" in the Insectivora and the latter doubtfully in the 

 Artiodactyla, but I have already suggested (Simpson, 1936b) that 

 they are probably hyopsodontids. Finally there are three new 



