rORT UNION OF CRAZY MOUNTAIN FIELD, MONT. 127 



Family MIXODECTIDAE Cope, 1883 



Previous views as to the affinities of tliis peculiar group have been 

 summed up by Matthew (1909, 1915, and Pale. Mem.). In briefer 

 resume, Cope considered the mixodectids as primates. Matthew 

 (1897) concurred formally but suggested that Mixodectes itself might 

 rather be a rodent. Osborn (1902) accepted and expanded this view, 

 defining for the mixodectids a rodent suborder Proglires. Wortman 

 (1903) argued for their return to the Primates, Finally, Matthew 

 (1909 and subsequently) concluded that they probably belong in the 

 Insectivora. 



Two very distinctive genera, Evdaemonema and Elpidophorus, have 

 recently been added to the family. They add to the known variety 

 and have an interesting bearing on relationsliips within the family, as 

 brought out below, but they do not much alter the evidence for ordinal 

 relationships. 



Skeletal remains referred to Indrodon by Osborn and Earle and to 

 Microsyops by Wortman, in each case considered as indicating primate 

 affinities, have been shown (Matthew, 1909) to be doubtfully or not 

 associated. An astragalus and other fragments referred to Mixodectes 

 were at first said by Matthew (1897) to be rodentlike and later (1909) 

 to be equally insectivorehke and in any case not similar to any known 

 primate. 



The dentition is said, even by Matthew in rejecting primate affini- 

 ties, to be primatehke. There is, indeed, some resemblance to various 

 primate genera in a few details, for instance the upper molars suggest 

 Shoshonius in general proportions and in the strong mesostyle, and 

 the enlargement of one anterior tooth and development of a diastema 

 by loss of other teeth are also seen in Tetonius and some other genera. 

 Such resemblances seem to have no value in the determination of 

 affinities, since they refer to single characters of various different 

 primates that are, in just these characters, highly aberrant among the 

 primates as whole. Aside from such points, which can almost be 

 discarded categorically as more likely to be convergent than not, I 

 detect no primate resemblances in the teeth that go beyond the general 

 Paleocene tuberculosectional pattern common to many different 

 orders at this time. As set forth in the section of this paper dealing 

 with the Primates, the Paleocene and Eocene primates, despite their 

 primitive character, do have a distinctive stamp in molar pattern that 

 is common to all of them and that is not seen to occur in any other 

 order. The mixodectids do not have any of these truly distinctive 

 and (at this time) ordinal primate characters. On the contrary, their 

 high sharp cusps (notably in the talonids), elevated trigonids and 

 internal lower cusps, displaced hypoconulids, and many other dis- 

 tinctive details are quite unkno^\Ti among any primates and some of 



