PLATE CI. 
OLIGOCENE RHINOCEROSES. HyRACODON 
Fries. 1-11. Hyracodon arcidens Cope, 1873. Typespecimen. Amer. Mus. No. 6309, Cope Coll., 
Cedar Creek beds (Oreodon zone) of Logan Co., Colorado. All figures two fifths 
nature. Fig. 1, palate and lower jaws, left side; fig. 2, palatal view of palate; 
fig. 3, occiput, posterior and right side views; fig. 4, superior view of lower jaws; 
fig. 5, fragment unidentified; fig. 6, atlas, inferior view; fig. 7, 7a, 7b, axis, 
lateral superior and inferior views; 8, 8a, 8b, 8c, 8d, middle cervical vertebra, 
lateral, superior, inferior, anterior and posterior views; 9, 9b, 9c, 9d, correspond- | 
ing views of first dorsal; 10, 11, anterior dorsals. 
