418 THE OSTEOLOGY OF VULPES MACROTIS. 



even still simpler, the trochlear head being less evidently denned. Vulpes macrotis 

 has the skeleton of its second toe equal in length to that of the fifth, and that of 

 the third equal to that of the fourth, — the bones all being strong, stoutish and well- 

 proportioned. The second toe has a length of about 3.4 centimeters, and the third 

 4.0 centimeters. These measurements include the ungual joints, and all the bones 

 normally articulated. In the case of any digit, its proximal joint is about one- 

 fourth longer than the next one beyond. For example, the length of the proximal 

 joint of the fourth digit is 1.8 cms., the next joint in the same toe being 1.4 cms., 

 and their calibres vary in proportion. The sharp-pointed angular joints exhibit but 

 little curvature, and at their articulations their basal portions extend plantar-wards 

 as a process, in each case, for the insertion of the plantar tendon of the flexor 

 longus digitorum. 



EXPLANATION OF PLATES. 



All the figures are of natural size, except fig. 12 of Plate XXIII, and from 

 photographs made direct from the specimens by the author. 



Plate XXII. 



Fig. 1. Left lateral view of the skull and lower jaw of Vulpes macrotis. 



Fig. 2. Dorsal aspect of the skull of Vulpes velox, the mandibles having been 

 removed. 



Fig. 3. Lower jaw or mandible of Vulpes macrotis, viewed from above. 



Fig. 4. Right ramus of mandible of Vulpes velox, seen from above, and 

 rotated inward. Tip of canine tooth, and the incisors broken off"; molars and 

 other teeth complete and in position. 



Fig. 5. Ventral aspect of the skull of Vulpes velox (same specimen as is shown 

 in fig. 2). The lower jaw has been removed. 



Fig. 6. Ventral aspect of the skull of Vulpes macrotis. 



Fig. 7. Dorsal aspect of the skull of Vulpes macrotis. Same specimen as is 

 shown in fig. 6. 



Plate XXIII. 



Fig. 8. Left scapula of Vulpes macrotis, external surface. 



Fig. 9. Dorsal surface of the left humerus of Vulpes macrotis, showing the 

 preaxial border, greater tuberosity, and the external condyle. 



Fig. 10. Anterior view of the left femur of Vulpes macrotis. 



Fig. 11. Left tibia and fibula of Vulpes macrotis, normally articulated, and 

 viewed upon external aspect. (All the bones, except those shown in figs. 2, 4, and 

 5, of PI. XXII, belong to the one and same individual in author's collection, the 

 ramus of the jaw in fig. 4, PI. XXII, belonging to the specimen of V. velox of the 

 U. S. Nat. Museum, No. 15,355.) 



Fig. 12. Right lateral aspect of the skeleton of the trunk of Vulpes macrotis. 

 (Reduced rather less than one-half.) Naturally articulated, and the dried ligaments 

 and cartilaginous costal ribs not removed. Exhibits the normal relations of the 

 bones of the trunk. 



