HIPPARION. 



181 



Hipparion whitneyi Gidley 1903. 



Plates 31.1,2, 32.1, 39.1,4, 51.3,6, Text Figs. 51, 144. 



Neohipparion whitneyi, gen. et sp. nov. Gidley, J. W. "A New Three-Toed Horse," Ball. Amer. Mus. Nat. Hist. Vol. XIX, Art. 

 XIII, July 24, 1903, pp. 467-476, no figure. Osborn, Henry Fairfield, "Ten Years' Progress in the Mammalian Palaeontology of North 

 America," Comptes rendus du 6me Congres intern, dc Zoologie (Session de Berne, 1904) May 25, 1905, PI. xi. 



Horizon and locality. — (Gidley) Little White River, near the Rosebud Indian Agency, South Dakota, Nebraska 

 formation, Lower Pliocene. Type discovered by H. F. Wells, collected by J. W. Gidley of the American Museum expedi- 

 tion of 1902. 



Type. — Amer. Mus. 9815. A complete skull and skeleton of an adult female individual immediately associated with 

 incomplete skeletons of five other individuals, immature, undoubtedly belonging to the same species. Measurements: 

 (Gidley, 1907). 



It) 



Fig. 144. Hipparion whitneyi Gidley, Amer. Mus. 9815. Crown view of the upper and lower grinding teeth of the 

 type. Natural size. Drawings by S. Oka. 



Measurements (in part) 



Diameters of p 1 , anteropost. 

 " p 2 , 

 « p3; 



" p<, 



" mS 

 " m 2 , 



095 



0295 



025 



025 



022 



024 



Total length of series 152 



Width across external incisors 055 



transv 007 



0235 



025 



0255 



023 



023 



Type figure. Plates 51, text Figs. 51, 144 of this Memoir. 



Characters. — (Gidley, 1907, p. 924) (1) Size about equal to Hipparion occidentale, but enamel foldings much 

 more simple, even more simple than in H. affinc; (2) H. whitneyi further differs from //. affinc in the much stronger 

 development of the styles of the ectoloph; (3) protocone relatively large and very much elongated in cross section antero- 

 posteriorly; (4) inner, or lingual, wall of the protocone flat and slightly depressed, as is usual in Equus caballus, 

 (5) Metapodials very long and slender; (6) lateral digits greatly reduced, their terminal phalanges not extending to the 

 distal end of the first phalanx of the median digit. 



A referred specimen is Amer. Mus. 9817, 



