SYNOPSIS 



GENERA AND SPECIES OF EXTINCT MAMMALIA AND CHELONIA DESCRIBED IN THIS WORK. 



MAMMALIA. 

 UNGULATA PARIDIGITATA. 



RUMINANTIA. 



POEBROTHERIUM. Hornless; without lachrymal fossae; auditory bullas very large and inflated; 



Qy Q? 



orbits closed by a post-orbital arch. Lower jaw with an angular apophysis. Dental formula: in. — ^ - 



c. ' — '- v.m. in. =38? True molars composed as in existing ruminants: premolars 



0?— 0? ^ 4—4 3 — 3 ^ ° ' ^ 



most like those of the recent Musks ; first premolar removed from the others by a hiatus. 

 PoEBROTHERiuM WiLSONii. Unique species. 



AGEIOCHOERUS. Hornless ; without lachrymal fossas ; orbits open behind. Dental formula : 



in. — '- c. ^ ' — '- p.m. —I '- m. := 44 ? True molars constructed after the type of those 



4?— 4? 1?— 1? 3?— 8? 3—3 



of existing ruminants ; premolars with from one to four lobes, modified in form from those of the true 



molars. 



Agriochoertjs antiquus. Unique species. 



OREODON. Hornless ; with a sagittal crest ; with the pars-squamosa of the temporal bone relatively 

 as well developed as in the Camel; auditory bullae none; orbits closed behind; very large lachrymal 



fossae. Dental formula : in. c. p.m m. = 44. Teeth of both jaws forming 



4 — 4 1 — 1 3 — 3 3 — 3 



nearly closed rows. True molars constructed after the type of those of existing ruminants ; premolars 



with one or two lobes. Upper canine with a curved, trihedral, pyramidal crown ; lower canine with a 



compressed conoidal crown. Incisors with flattened crowns. 



1. Oreodon Culbertsonii. About the size of the Wolf of Pennsylvania. 



2. Oreodon gracilis. About two-thirds the size of the former. 



3. Oreodon major? A little larger than Oreodon Culbertsonii. 



EUCROTAPHUS. Cranium constructed like that of Oreodon, except that it possesses large, inflated 

 auditory bullae. Dental formula : as in Oreodon ? 



1. EucROTAPHUS AURITUS. Auditory bullae laterally compressed spheroidal. 



2. EuCROTAPHUS Jaoksoni. Smaller than the preceding ; auditory bullae mammillary. 



