ORDER CARNIVORA. 



1451 



Upper Miocene of North America is remarkable as being the only 

 known Mammal, except certain Edentates and Cetaceans, in which 

 the pterygoids unite beneath the nasal passage. One of the Euro- 

 pean forms was originally described as Taxotherium. In the allied 

 Pterodon, which, together with Oxhycena, some writers refer to a 

 distinct family, the third upper true molar is present, and has a 



Fig. 1336. — Right lateral aspect of the dentition of Hyanodo?i horridus, wanting the teeth in 

 advance of the second lower premolar ; from the Miocene of North America. Reduced. (After 

 Leidy.) 



transversely elongated crown ; there may be either two or three 

 upper incisors, and the first lower premolar is sometimes absent. 

 The first and second upper true molars differ from those of 

 Hycsnodon by the large size of their inner tubercle, and the last 

 true molar is like the second ; the cranium in many respects 

 resembles that of Amphicyon. This genus is represented by 



Fig. 1337. — The left side of the anterior half of the palate of Oxhycena gallice ; 

 from the French Phosphorites. 



three comparatively large species from the Upper Eocene (Lower 

 Oligocene) of Europe. An allied form, from the French Phos- 

 phorites, has been named Psendopterodon, and connects the former 

 genus with Theitritherium. The remarkable genus Oxhycena, of the 

 North American Eocene and the French Phosphorites, has an elon- 



(2-7.) 

 gated mandibular symphysis, with the dental formula /. v — - , 



o 

 4 



C. 



Pm. -, M. - ' f the species figured in the woodcut having only 



