1 68 STUDIES FOR STUDENTS 



(i) certain portions of the Indo-Malayan region, and (2) the 

 tropical parts of America." 



Lophiodontidae . — In defining this family Osborn and Wort- 

 man indicate its position by referring to it as "A family of 

 Lophodont Perissodactyls intermediate in position between the 

 Tapiridae and the Hyracodontidae . The genera referred to this 

 family are Lophiodon from the Middle Eocene of Europe, Hepto- 

 don of the Wasatch, Helaletes of the Bridger and Uinta, and 

 Colodon of the White River. 



Lophiodon has been considered as a very widely spread form 

 in the Middle Miocene of Europe, but it now seems to be the 

 opinion that many species have been wrongly referred to it that 

 should properly be placed with genera Colodon and Helaletes. 



The Chalicotheroidea is sometimes regarded as a separate 

 suborder, the Ancyclopoda not being related directly to the Peris- 

 sodactyls. They were aberrant animals related on the one hand 

 to the Perissodactyls and on the other to the Edentates. In the 

 structure of the foot there is a striking resemblance to the struc- 

 ture in the great ground sloths, Gravigrada, of the late Tertiaries 

 of America. It was five-toed and turned so that the weight of 

 the animal rested upon the outer side of the foot, and the digits 

 terminated in strong claws. The teeth, on the other hand, were 

 strikingly like the teeth of the Perissodactyl series. The sub- 

 order, or super-family, had its greatest development in the Mio- 

 cene and Pliocene times. 



Homalodontotherium is from the early Tertiary deposits of 

 Patagonia. The primitive character is indicated by the complete 

 dentition of the animal and the absence of any diastema. The 

 humerus was very short and stout, indicating possible fossorial 

 habits. 



Macrotherhmi is a smaller form from the Middle Miocene of 

 France and Germany. The condition of the teeth indicates a 

 somewhat more advanced type. The fore limbs were much 

 longer than the hind. The best known species was about nine 

 feet in length. 



Chalicotherium is the best known form from the United States. 



