NO. 2086. 



SOME MAMMALS OF THE PLEISTOCENE— HAY. 



547 



The greatest diameter at the middle of the femur is taken through 

 the ridge which descends from the third trochanter. This is more 

 prominent in E. francisci than in E. hemionus. Also, as shown' by 

 section, the marrow cavity in E, hemionus is of less diameter than 

 is the fossil species, and the bone of the shaft is considerably thicker. 

 In the fossil the ridge which descends from the lesser trochanter is 

 more prominent than in E. hemionus. 



Both patellae are present. 





Measurements of patella in millimeters. 









E. 

 francisci. 



E. 

 hemionus. 



Arabian. 



Total length 



54 

 55 

 26 



57 

 56 

 27 



74 



Greatest width 



74 



Greatest thickness 









The tibiae are represented by a fragment of the upper end of that 

 of the left side ; that is, the articular surface for the outer condyle 

 of the femur. There is also a large part of the shaft of the one of 

 the right side, including the distal end; also a part of the upper 

 articular surface for the inner condyle of the femur. The length of 

 the bone can not be determined with exactitude, but by comparison 

 of similar surfaces and markings it is estimated that the length was 

 not much less than that of the tibia here assigned to Equus lauren- 

 tius (p. 569), which is 322 mm. The total length of the fragment 

 of the right tibia is 220 mm. The nutrient foramen is not present, 

 but could not have been far away. 



Measurements of the tibia in (millimeters. 



— t 



E. 



francisci. 



E. 

 hemionus. 



Arabian. 



Total length 



Diameter of upper end, greatest, side to side 

 Diameter at middle of length, fore and aft. . 

 Diameter at middle of length, side to side. . . 



Diameter at distal end, side to side 



Diameter at distal end, fore and aft 



±30 



±35 



55 



38 



332 

 83 

 29 

 37 

 63 

 40 



380 

 102 

 36 

 40 

 80 

 51 



The diameters taken at the middle of the length are very close to 

 the true ones. The difficulty is, of course, to determine exactly where 

 the middle of the length is. The fragment of the left tibia does not 

 extend across the proximal end. The surface for the outer condyle 

 of the femur measures along its outer border 44 mm.; along the 

 diameter at right angles to this, 36 mm. 



All the bones of the left hind foot are present except the hoof 

 phalange and the sesamoids. Parts of the shaft of the third meta- 

 tarsal are gone, but there is connection throughout the length of the 

 bone. The distal halves of the second and fourth metatarsals are 



