280 Loomis — Wasatch and Wind River Primates. 



medianly, suggesting 



Fig. 

 x4. 



Anaptomorphus abbotti, type 



a hypoconulid. The third premolar 

 is two-rooted, and has but a 

 single cusp. Its posterior (un- 

 guium is also raised medianly, 

 suggesting a forming cusp. 



Specific features are found 

 in the external cingulum of 

 the molars, the elongated 

 talonid of molar three and in 

 the raised posterior cingnlum 

 of the third and fourth pre- 

 molars. 



Nine specimens were found 

 on JBridger Creek in the 

 Wind River beds. 



The three molars measure 

 7 mm in length and molar 2 is 

 2 mm wide. 



Adapidae Schlosser* 



In this family the American genus .Notharctus approaches 

 the European genus Adapis closely, especially the new species 

 N. minutus from the Wind River. Two genera are represented 

 in America, the simpler and apparently ancestral Pelycodus 

 from the Wasatch, and the more advanced Xotharctus of the 

 Wind River and Bridger. 



The family may be defined as follows ; dentition if e\ pm|- 

 mj- ; molars low crowned and with low cusps ; paraconid reduced 

 but present ; external cusps more or less crescentic; hypoconid 

 small ; the last lower molar with a weak and varying heel. 



The family makes its appearance in Europe and America 

 suddenly and at almost the same time, apparently migrating 

 from some northern center of distribution onto the two con- 

 tinents ; the climate being a warm temperate or tropical one, 

 as shown by the faunaf and flora collected in the basal beds 

 of the Wasatch by the Amherst expedition. 



The two genera are distinguished as follows : 



Pelycodus 

 Outer cusps of lower teeth more 



or less conical : 

 No mesostyle on upper teeth : 

 Hypocone weak : 

 Heel of last lower molar large, 



tending to have two or more 



cusps: 

 Fourth lower premolar simple. 



Notharctus 



Outer cusps of lower teeth more 



or less crescentic : 

 Mesostyle on upper teeth : 

 Hypocone strong : 

 Heel of last lower molar weak 



with a single cusp only : 



Fourth lower molar complex. 



*Affer, Lemuren, Chiropteren, etc., 1887, Pt. 1, p. 21. 

 f Wortraan, this Journal, 1903, p. 419. 



