Fia. 
Fia 
lia 
Fia. 
PLATE CXI. 
JoHun Day DicoryLINEsS AND OREODONTS 
Nomenclature 
Cope 1880-3 
Cheenohyus decedens 
Paleochcerus pristinus 
Paleochcerus socialis 
Coloreodon ryderanus 
Revised 1915 
Chenohyus decedens 
Perchcerus pristinus 
Perchcerus socialis 
Agriochcerus ryderanus 
Chenohyus decedens Cope, 1879. Side and top views of anterior half of skull. Type 
specimen, Condon Coll., University of Oregon. See pl. CXa, fig. 3. Natural 
1, la. 
size. 
. 2. Percherus pristinus (Leidy 1873). 
size. 
. 3. Percherus socialis (Marsh, 1875). 
size. 
4. Agriocherus ryderanus (Cope, 1881). 
Coll. side view, natural size. 
fourths natural size. 
Lower jaw, Am. Mus. No. 7392, Cope Coll. Natural 
Lower jaw, Am. Mus. No. 7393, Cope Coll. Natural 
Skull, type specimen, Am. Mus. No. 7407, Cope 
Figs. 4a, 4b, superior and inferior views, three- 

