MIOHIPPUS. 



57 



of p 1 . (5) Hypostyle and transverse crest still connected with posterior cingulum, a distinct pli hypostyle; (6) internal 

 cingulum persisting, especially evident on the premolars; (7) ectoloph more elevated than metaloph. Other special 

 characters which appear to be distinctive are (8) the crenulation of the enamel surface of the premolars, and (9) a rudi- 

 mentary spur or crochet, pli crochet, on the metaloph of p 3 , nr; (10) external cingulum tending to cross base of parastyle; 

 (11) protoloph longer than metaloph in the premolars. 



A rudimentary crochet observed in M. gidleyi is also seen in m 3 of M. intermedins. 



This species appears to be confirmed by a referred specimen, Princeton Mus. 10501, which is slightly more progressive. 

 It is named in honor of J. W. Gidley, the leading explorer for fossil horses under the William C. Whitney Fund of the 

 American Museum of Natural History. 



Fig. 34. Miohippus gidleyi Osborn, Am. Mus. 1192. (Right upper) Original figure of skull of type. One-half 

 natural size. (Left upper) Original figure of crown of m 1 of type. Natural size. After Osborn, 1904, skull PI. v, G, 

 tooth fig. 8, p. 178. (4) Crown view of superior molar-premolar series of type. Natural size. 



Miohippus crassicuspis Osborn, 1904. 

 Plate 3.11. Text Fig. 35. 



Miohippus crassicuspis, sp. nov., Osborn, Henry F. "New Oligocene Horses," Bull. Amer. Mus. Nat. Hist., Vol. XX, Art. XIII, 

 May 28, 1904, pp. 178-179, no figure. 



fis 



pS /2 



Fig. 35. Original figure of type Miohippus crassicuspis Osborn, Amer. Mus. 683, p 2-3 of the right side. Natural 

 size. After Osborn, 1895, fig. 5, p. 357. 



The teeth represented in this figure when first published (Osborn and Wortman, 1895, fig. 75, p. 357) were mistakenly 

 referred to Mesohippus (= Colodon) copei. 



Horizon and locality. — Big Badlands, Cheyenne River, South Dakota, Protoceras zone. Type collected by American 

 Museum Expedition of 1S92. 



