1088 The Artiodactyla. 
Canines large, the inferior received into a deep excavation in 
front of the superior canine ; premolars 4; fourth with one lubercle ; 
Bothrolabis Cope. 
Like Bothrolabis, but premolars 3....... .... .... Chanohyus Cope 
II. Digits three. 
I. Metapodials fused proximally (Dicotylinz). 
a. Premolars like molars ; a deep notch in front of superior 
canine. 
Premolars 2; cusps of molars separate........... .......Dicotyles Cuv. 
Premolars 3; cusps of molars united into partial cross-crests 
; Platygonus Lec. 
III. Digits two (Elotheriinz). 
Superior canines decurved ; last inferior molar without heel ; 
Elotherium Pom. 
t 
y 
Fria, 4,—Ocenotherium filholi Lydekker, superior and inferior views of 
the Eocene of Caylux, France. Natural size. From Lydekker, 
` The genera of Hippopotamine are all Old World. While a single 
living species represents each of the genera Hippopotamus an 
Chceropsis, there are several extinct species of Hippopotamus and 
Hexaprotodon. ‘hese are chiefly confined to the Upper Miocen? 
skull, from 
