PLATE 52 



HIND FEET OF MERYCHIPPUS ISONESUS SECUNDUS, M. I. TERTIUS, M. I. QUARTUS. 

 COMPARISON OF PES IN THREE SPECIES FROM THE SHEEP CREEK BEDS OF NEBRASKA. 



All figures one-half natural size. 



Sheep Creek, Nebr. Middle Miocene 1. Merychippus isonesus secundus Osborn, type, Am. Mus. 14179. Asso- 

 ciated with fragments of jaw, teeth, and parts of skeleton, a, Anterior, 

 b, external view. 



" " " " 2. M. isonesus ieriius Osborn, type, Am. Mus. 14180. Associated with skele- 



ton. Anterior view. 



" 3. M. isonesus quartus Osborn, type, Am. Mus. 14184 (reversed in drawing), 



a, anterior, b, external view. Associated with other skeletal parts, 

 lacking skull and teeth. 



32H 



