CLASSIFICATION OF VERTEBRATA 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. 



Dinotheriidae. No upper incisors, lower pair transformed 

 into down-curved tusks. 



Dinotherium. Miocene of Europe and India. 



Mephantidae. Mastodon with upper and lower tusks. 

 Miocene and Pliocene of Europe, India, North America ; 

 Plistocene of North, Central, and South America. 



Elephas, with upper tusks only. Since the upper Miocene 

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

 North and South America. Eeeent in Africa, India, Ceylon, 

 Sumatra. 



5. Sub-order CONDYLAETHEA, Cope. Plantigrade, with 

 toes. Carpalia serial. Dentition complete. Eibula com- 

 plete, 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 LITOPTEENA, Ameghino. Digitigrade. 

 Carpalia 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 PEEISSODACTYLA (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 |k Since the Eocene of America and Europe. 

 Lophiodon. Eocene of Europe. 

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



