Douglass : Fossil Horses. 275 



Length of symphysis of mandible 49 



Length of femur exclusive of proximal symphysis 233 



Length of radius 218 



Least antero-posterior diameter of femur 30 



Length of median metapodial 194 



Transverse width of shaft of median metapodial 17.5 



Length of ungual phalanx 32.5 



Width of ungual phalanx 19 



Of the paratype (No. 858) there is, besides other bones, a nearly 

 complete hind foot. The specimen was of nearly the same age as the 

 type and the bones so far as shown have the same sizes and propor- 

 tions. A figure of the foot of the paratype is given on Plate LXVII, 

 fig- 5- 



Merychippus insignis Leidy. 



(Plate LXVII, figures i and 2; Plate LXV1II, figures 3-5.) 

 Proc. Acad. Nat. Sci. Phila., Vol. VIII, 1856, p. 311. 

 This specimen, N6. 1377, Carnegie Museum Catalogue of Verte- 

 brate Fossils, consists of a portion of a maxillary with incomplete 

 upper teeth, the horizontal rami of a mandible with the molar-premolar 

 series of both sides, three metapodials of one foot, a femur and por- 

 tions of other limb and foot bones. This specimen was found in the 

 Miocene deposits on Deep Creek, southeast of Townsend in Broad- 

 water County, Montana. As no other fossils were found in these 

 deposits at this place the exact horizon cannot be determined. The 

 specimen was collected by Earl Douglass in 1898. 



Distinguishing Characters. — (1) Upper cheek-teeth transversely 

 narrow, (2) enamel lakes comparatively simple, each having from one 

 to three enamel-folds which are usually small, (3) protoconeand hypo- 

 cone of nearly equal size and connected respectively with the protoco- 

 nule and metaconule, (4) symphysis of mandible shallow, but hori- 

 zontal rami increasing quite rapidly in depth posteriorly, (5) Pj- absent, 

 (6) teeth of molar-premolar series decreasing in size from P-3 to M-g-, 

 and decreasing in length from P^ to M^, (7) metapodials compara- 

 tively short, (8) lateral digits small, (9) femur long, being one and one 

 half times the length of the metapodials. 



Measurements. 



mm. 



Length of lower-premolar series io 9-5 



Length of P^ 21 



