Douglass : Verteijratks ikom Montana Tertiary. 



1(57 



The auditory bulla is lost on one side and present on the other. 



This lends weight to the probability that the absence of the bullae in 



some of the skulls of fossil dogs does not prove that the animals did 



not possess them in life. 



Measurements. 



Mm. 



Length of skull to posterior of tympanic bulla 133 



Width of skull, including zygomatic arches, greatest 80 



Width at postorbital constriction 23 



Length of molar-premolar series 51 



ARTIODACTYLA. 



Lepto.meryx transmontanus sp. nov. 



No. 726. Fig. II. 

 This is larger than L. evansi and the teeth more advanced, the 

 infraorbital foramen is a little farther back than in the specimen 

 described by Leidy in his Extinct Mammalian Fauna. It opens 



Fig. II. Leptonteryx transtnontantis (No. 726). John Day, near Drummond. 

 Natural size, a, skull ; b, crown view of teetli. 



above the anterior portion of P''. There is a prominent malomaxil- 

 lary ridge which extends forward on the face as far at least as the 

 anterior part of P^. 



