NO. 2086. 



SO ME MAMMALS OF THE PLEISTOCENE—HAY. 



545 



determine the length of the bone. The following dimensions are 

 given as in the species compared : 



Measurements of the humerus in millimeters. 



Length, total 



Length from upper surface of the head to inner side of distal end. 



Diameter, through the head and tuberosities, greatest 



Diameter, greatest at middle of length 



Diameter, side to side at middle of length 



Diameter, across the lower articular surface 



E. 

 francisci. 



28 ± 

 60 



E. 



hemionus. 



260 

 236 

 83 

 42 

 30 

 63 



Arabian. 



317 

 300 



50 

 37 

 80 



The left radius has missing a part of the shaft, but the fragments 

 connect in front. The right radius is complete and is accompanied 

 by a part of the proximal end of the ulna. The following are the 

 measurements secured. In the second column under each specific 

 name are presented, as indices, the value of each measurement when 

 compared with the length taken as 100. 



Measurements of the radius in millimeters, with indices. 





E. francisci. 



E. hemionus. 



Arabian. 





Mm. 



Indices. 



Mm. 



Indices. 



Mm 



Indices. 



Length from articular surface above to that below, 

 on outer border of the bone. 



288 

 69 

 23 

 33 

 59 

 49 



100 



24 



8 



11.4 

 20.5 

 16 



300 

 69 

 23 

 35 

 66 

 54 



100 

 23 



7.7 

 11.7 

 22 

 18 



352 



85 

 29 

 40 

 80 

 67 



100 



Diameter of upper end, greatest 



24.2 



Diameter at middle of length, fore and aft 



8.2 



Diameter at middle of length, side to side 



11.3 



Diameter at lower end, greatest from side to side 



Distance across lower articular surfaces, side to side 



22.7 

 19 



An examination of this table shows that the radius of E. francisci 

 stands in slenderness between that of E. hemionus and the Arabian 

 horse, but the distal end is narrower than that of either of the two 

 last named. It is to be observed further that this radius lacks only 

 2 mm. of being as long as that of the horse whose limbs are in this 

 paper assigned provisionally to E. laurentius (p. 569), while the 

 diameters at the middle of the length are far less. The ulna, at the 

 rear of its union with the radius, has a diameter of 33 mm. In Equus 

 hemionus it is 42 mm. 



Of the ossa innominata there are present three fragments of the 

 right side and four of the left. All parts of the latter are present 

 except the anterior outer process of the ilium, that part of the ischium 

 which enters into the acetabulum and forms most of the hinder 

 boundary of the ischiopubic foramen, and the tuberosity. From the 

 fact that some fragments of the pelvis are missing it is not possible 

 to give all the measurements desired. If a line be drawn from the 

 extremity of the suprailiac crest to the ischial border of the os 

 innominatum, at right angles to this border and following the curva- 

 ture of the bone, the distance is 175 mm. In E. hemionus the dis- 

 59758°— Proc.N.M.vol.48— 14 35 



