ORDINAL TYPES OF MOLARS: INSKCTIVORA 



121 



FIG. 70. Lower jaw and teeth of Apternodus medicevus. From the Oligocene of Montana. Pro- 

 visionally assigned to the Insectivora, but possibly allied to the Cheiroptera (Matthew). The 

 talonid is represented by the minute posterior basal spur. A, upper, At, external and A- internal 

 views. X T . After Matthew. The molars somewhat resemble those of certain Mesozoic trituber- 

 culates (e.g. Permnus, Fig. 18, Peraspalar, Fig. 22). 



FIG. VI. 



FIG. 73. 



FIG. 71. Lower jaw and teeth of Micropternodus borealis. From the Middle Oligocene of 

 Montana. Probably allied to the Zalarabdodont Insectivores. x J. After Matthew. 



FIG. 72. Upper molars of one of the Centetid;u (Ericulus setosus) viewed obliquely from the 

 rear,, showing resemblances to the teeth of the Upper Jurassic genus Kurtodon (Fig. 13). Compare 

 also Fig. 207, No. 2. x |.. From a specimen at Yale University (Peabody Museum). 



Fio. 73. Inferior view of skull and teeth of Proscalops mioccenus, a primitive Mole from the 

 Upper Oligocene of Colorado, x r . After Matthew. 



