166 



UNGULATA 



ORDER VII 



and delicate ; mandible reduced in length anteriorly but symphysis heavy ; 

 short muzzle ; brachycephalic. This genus is founded on the front of skull 



Fig. 224. 



Macrotherium gigantnvm Gervais. Middle Miocene, 

 Sansan (Gers), France. A, Left fore-foot. B, Left 

 hind-foot, with separate upper view of astragalus (a). 

 i/g. (After Gervais.) 



Flo. 225. 



Chalicotherium goldfassi Kaup. 

 Lower Pliocene, Eppelsheim, Hesse- 

 Darmstadt. A, Second upper molar. 

 B, Last lower molar. 2/3. 



and lower jaw of Chalicotherium (Anoplotherium) sivalense Falc. and Caut., from 

 the Pliocene of the Siwalik Hills, India. 



The following is of uncertain position : Chalicotherium bilobatwn Cope, 

 Oligocene ; Swift Current River, Canada. 



Suborder D. ARTIODACTYLA Owen. (Paraxonia Marsh.) 

 Even-toed Ungulates.^ 



Unguligrade or digitigrade ungulates with an even number of digits, the two 

 middle of which are equally developed and much stouter than the lateral ones, which 

 are often much reduced or aborted. Astragalus with ginglymoid trochleas proximally 

 and distally. Carpal and tarsal bones alternating. Dentition complete, or incisors 

 ami canines absent, espedally in the upper jaw. Cheek teeth bunodont, bunoselenodont, 

 or selenodont. Femur without third trochanter. Fibula articulating with the 

 calcaneum. 



In contrast to the decadent perissodactyls, the artiodactyls constitute an 

 existing group the most abundant in forms, the most dominant, and the 

 most widely distributed of all the ungulates. They culminate in the 

 bunodont suillines and the selenodont ruminants, which difi'er strikingly 



1 Cope, E. D., The Artiodactyla. Amer. Naturalist, vol. xxii., 188S ; vol. xxiii., 1889. — 

 KoitKilevsky, W., Palaeontograpbica, vol. xxii., 1873-74. — Sinclair, W. J., Bimodout Artio- 

 dactyla of Lower and Middle Eocene of North America. Bull. Amer. Mus. Nat. Hist., 1914. — 

 Stehlin, H. G., Siiugetiere des Schweizer. Eocans. Abli. Schweiz. paluout. Ges., vol. xxiii., 1906 ; 

 XXV., 1908 ; xxvii., 1910. 



