92 



OSBORN: OLIGOCENE, MIOCENE, PLIOCENE EQTJIDjE. 



somewhat earlier geologic age than the Mascall, consists of part of the skull, jaws, and a large part of the skeleton. 

 This agrees with the type in the presence of cement, and agrees with various species of Merychippus in the abbrevia- 

 tion of the metapodials, measuring Mtc. Ill .165. 



MERYCHIPPUS PANIENSIS-M. SEJUNCTUS ZONE. 10. LATE MIDDLE MIOCENE. 



This life zone is typified by the Pawnee Creek of northwestern Colorado, which contains a great variety 

 of Merychippvs. 



Parahippus pawniensis Gidley 1907. 

 Plates 8.5, 9.3. Text Figs. 68, 69. 



Parahippus pawniensis sp. nov., Gidley, J. W. "Revision of the Miocene and Pliocene Equidse of North America," Bull. Amer. 

 Mas. Nat. Hist., Vol. XXIII, Art. XXXV, Nov. 26, 1907, p. 932, no figure. 



Horizon and locality. — Cedar Creek, Pawnee Creek formation, northeastern Colorado, Middle Miocene. Type col- 

 lected by Handel T. Martin, American Museum Expedition of 1898. 



Fig. 68. Parahippus pawniensis Gidley, Amer. Mus. 9085, crown view of the upper and lower dentition of the type. 

 Natural size. 



Type— Amer. Mus. 9085. The upper and lower cheek teeth of one side, and fragments of the skeleton, including 

 parts of the feet. Measurements: (Gidley) p 2 -m 3 (approximately) .092; m 1 " 3 .0462; p* a. p. .072, tr. .0201; m 1 a. p. 

 .0178, tr. .020. 



Type figure — Plates S.5, 9.3, text Fig. 68 of this Memoir. 



Characters— (Gidley, 1907, p. 932) "(1) Cheek teeth shorter crowned than in any other species hitherto described; 

 (2) the metaloph in the upper teeth is comparatively straight, with enamel walls simple except for the median anterior 

 fold, or crochet; (3) crochet slightly united with the protoconule at its base; (4) external walls of paracone and metacone 

 relatively flat, as in P. crenidens, with only a faint indication of the median rib; (5) crowns of upper cheek teeth proportion- 

 ately narrower than in P. crenidens; (6) the metastylid in the lower teeth less prominent and less distinctly separated from 



