548 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



vol. 48. 



gone. Of the right foot there are present the astragalus, the cal- 

 caneum, the cuboid, three fragments of the third metatarsal and the 

 upper third of the second. To the writer it appears possible that 

 the second phalange in the mounted left hind leg is really that of 

 a fore foot, since the width of its upper articular surface is about 

 3 mm. greater than that of the distal end of the first phalange. The 

 astragali of both sides are complete. 



Measurements of the astragalus in 



millimeters. 







E. 

 francisci. 



E. 



hemionus. 



Arabian. 



Length of longest diagonal across upper articular surfaces 



60 

 40 



65 



42 



80 



Width across distal articular surface 



56 







Both calcanea are preserved. The following measurements are 

 presented : 



Measurements of the calcaneum in millimeters. 



Extreme length 



Depth of tuber calcis at middle of length. 



E. 



francisci. 



E. 

 hemionus. 



104 

 38 



Arabian. 



119 

 44 



The navicular has a side-to-side diameter of 39 mm. and a thick- 

 ness of 9 mm. in front. The external cuneiform has corresponding 

 diameters of 38 mm. and 11 mm. ; the middle cuneiform measures on 

 its hinder face 27 mm. from side to side; vertically, 16 mm. The 

 cuboid has the greatest diameter, 34 mm. ; the vertical diameter, 21 

 mm. ; and the side-to-side diameter, 14 mm. At its distal end each 

 presents an articular surface for the fourth metsflhrsal. The 

 greater part of both third metatarsals is preserved. That of the 

 right side is in three pieces and portions between them are miss- 

 ing. On the left side the bone is continuous from one end to the 

 other. The following measurements and indices are furnished: 



Measurements of the third metatarsal in millimeters, with indices. 



Lenth along outer border 



Side-to-side diameter at upper articular surface 



Fore-and-aft diameter at middle of length 



Side-to-side diameter at middle of length 



Distance across lower articular surface 



E. francisci. 



E. hemionus. 



Ar 



mm. 



indices. 



mm. 



indices. 



mm. 



225 



100 



257 



100 



290 



39 



17.3 



39 



15.1 



53 



25 



11.1 



25 



9.7 



33 



26 



11.2 



27 



10.5 



33 



34 



15.1 



40 



15.5 



53 



indices. 

 100 

 18. 

 11. 

 11. 

 18. 



A study of this table shows that while the median metatarsal of 

 E. francisci is a shorter bone than that of either of the other species, 

 it is intermediate between them in its diameters relatively to its 



