286 F. B. Loomis — On Ticholeptus Rusticus and 



Lower jaw, length of dental series . 132 



length of premolars 48 



length of molar series 74 



Fourth cervical vertebra, length 22 



Fourth dorsal- vertebra, length 24 



Second lumbar vertebra, length 30 



Humerus, length 153 



Eadius, length 124 



Metacarpal III, length 63 



Tibia, length 151 



Metatarsal III, length 64 



In order to place this skull it was necessary to make a 

 comparative study of most of the genera of this family 

 and as no such comparisons have been made for a long 

 time, especially since the knowledge of many of the best 

 known forms, I should like to offer the following notes 

 and suggestions for the distinctions of various of the gen- 

 era and for the relationships of different members of the 

 family. In the case of many species which are founded 

 on fragmentary jaws especially it is not possible to place 

 them definitely. 



Oreodontince. 



Selendont artiodactyls, with the dentition typically 

 I, \, h I and the teeth in closed series, the lower canine 

 incisof orm and the first premolar functioning as a canine ; 

 the feet with four functional toes. 



A. Toes clawed, external crescents of molars strongly concave, 



teeth brachydont, orbit open behind — Agriochoeridas. 

 I — Upper premolar 4 not molariform, protoconule present — 



Protagriochoerus. 

 II — Upper premolar 4 molariform, protoconule absent — 

 Agriochoerus. 



B. Toes hoofed, external crescents of molars little concave, pre- 



molar 4 never molariform — Oreodontidaa. 

 I — orbit open behind, incisors -J — Protoreodon. 



incisors lacking in upper jaw — Hyomeryx. 

 II — Orbit closed behind ; 



1 — limbs of moderate length ; 



a — digit 1 in manus present as vestige, bulla small 



— Oreodon. 

 b — (digit 1 unknown) bulla large — Eucrotaphus. 

 c — digit 1 lacking, bulla large, teeth brachydont — 

 Eporeodon. 



