174 



UNGULATA 



ORDEK VII 



whole more with the Anthracotheriidae than with the Suidae. Oligocene; 



Ronzon and Lobsann (Alsace), and Quercy Phosphorites. Also White River 



Oligocene, John Day beds and Lower Miocene of North America. 



Dinolmjiis Peterson (Fig. 233). Proportionally short alveolar border of 



premaxilla with incisors more crowded, the median one reduced; chin short, 



p 3 nearly square in 

 outline, p 4 with large 

 deuterocone, lower 

 molars with subequal 

 height of posterior and 

 anterior tubercles which 

 are separated by narrow 

 cross valleys. Trap- 

 ezium absent, fibula 

 co-ossified Avith the tibia. 

 Miocene ; Nebraska. 



Palaeochoerus Pomel 

 (Figs. 234, 235). Teeth 

 in nearly continuous 

 series. Canines not 

 much stronger developed 

 than incisors and pre- 

 molars. Superior and 

 inferior molars quadri- 

 tubercular, with basal 

 pj^. 235 cingulum. Last inferior 



PaJaeochoerus wafcrhousi Fomel. Lower Miocene, St. Gerand-le-Puy, molar Wlttl talOniCl. 



- B, c, Upper and Lower Miocene; Europe. 

 P. meisneri Meyer. P. 

 typus Pomel. Middle Miocene. P. aurelianensis Stehlin. 



Propalaeochoerus Stehlin. Oligocene Phosphorites ; Quercy. 



Choerofhermm Dep6ret (Colohus Fraas). Cheek teeth small and very simple. 

 Upper Miocene ; Sansan, Steinheim, etc. 



Xenochoerus Zdarsky. Premolar very complicated, molar- like. Upper 

 Miocene ; Styria. 



Hyotherium Meyer 

 (Fig. 236). Like Pdaeo- 

 choerus, but larger. Pre- 

 molars more strongly 

 compressed and elongate, 

 and fourth premolar in 

 both jaws complicated. 

 Superior canines with 

 divided root. Cusps of molars angular. Middle and Upper Miocene ; 

 Europe. H. soemmeringi Meyer. Pliocene 1 Siwalik, India. H. perimense 

 Lydekker. 



Perchoerus Leidy. Oligocene ; "White River beds. Chaenohyiis and 

 Bothrolabis Cope. Desmathyus Matthew. Lower Miocene. Thinohyus Marsh. 

 Upper Miocene of North America. These are Palaeochoeroid predecessors of 

 Dicotyles. 



AUier. A, SkuU and lower jaw, lateral aspect, 

 lower teeth. 1/2- (After Filhol.) 



Hyotherium soemmerinfii Meyer. Upper Miocene, Eibiswald, 

 Steiermark. Upper jaw. 1/0. (After Peters.) 



