CLASSIF1CA TION OF I r ER TEBRA TA 46 



One or two pairs of incisors transformed into tusks, 

 canines absent. With a long proboscis. 



Placenta zonary, deciduous. Mammae pectoral. 

 During the Miocene cosmopolitan, excluding Australia, 

 Now palaeotropical. 



J)iimtli<riidae. No upper incisors, lower pair transformed 

 into down-curved tusks. 



Dinotherium. Miocene of Europe and India. 

 Elephantidac. Mastodon with upper and lower tusks. 

 tiocene and Pliocene of Europe, India, North America ; 

 'listocene of North, Central, and South America. 



Elephas, with upper tusks only. Since the upper Miocene 

 India. Plio- and Plistocene of Asia, Europe, North Africa, 

 Torth and South America. Recent in Africa, India, Ceylon, 

 Sumatra. 



5. Sub-order CONDYLARTHRA, Cope. Plantigrade with 

 toes. Carpalia serial. Dentition % complete. Fibula com- 

 pete, but not articulating with either calcaneum or astragalus. 



Dentition complete. 



Eocene of North America and Europe. 



Periptychus and Meniscotherium. Lower Eocene, U.S.A. 



Phenacodus. Lower Eocene of U.S.A. and Europe. 



6. Sub-order LITOPTERNA, Ameghino. Digitigrade. 

 1'arpalia and tarsalia serial. Fibula complete, articulating 

 with the calcaneum and astragalus. Feet perissodactyle. 



Tertiary epoch of South America. 



Macrauchenia. Miocene to Plistocene. 

 Protherotherium. Eocene and Oligocene. 



7. Sub-order PERISSODACTYLA (Cuvier), Owen. Digiti- 

 grade. The third toe forms the functional axis. Carpalia and 

 tarsalia alternating. 



Fibula, when complete, articulating with the astragalus, not 

 with the calcaneum. 



Placenta diffused, non - deciduous. Mammae inguinal. 

 Stomach simple. Caecum large. 



Tapiridae. Lower molars with two transverse ridges. 

 Toes |. Since the Eocene of America and Europe. 

 Lophiodon. Eocene of Europe. 

 Heptodon, Helaletes. Eocene of U.S.A. 



