The =large= or =third metatarsal= bone is about one-sixth longer than the corresponding metacarpal; in an animal of medium size the difference is about two inches. The shaft is more cylindrical, and is almost circular on cross-section, except in its lower part. At the upper part of its external surface there is a groove, which is directed obliquely downward and backward, and is continued by the furrow formed by the apposition of the external metatarsal bone; it indicates the course of the great metatarsal artery. A faint impression in a similar place on the inner side marks the position of the corresponding vein. The nutrient foramen is relatively higher than on the metacarpal bone. The proximal extremity is much wider from before backward than that of the metacarpal bone. Its articular surface is slightly concave, and is marked by a large central non-articular depression, continued outward by a deep notch. The greater part of the surface articulates with the third tarsal, but there is an outer facet for the fourth, and usually a small facet posterointernally for the second tarsal bone. Posteriorly there are two pairs of facets for articulation with the small metatarsal bones. The front is crossed by a rough ridge for insertion, which becomes larger and turns downward on the outer side behind the vascular groove. The distal extremity closely resembles that of the corresponding metacarpal bone. In some cases the lower part of the shaft is bent backward somewhat. The articular surface extends a little higher behind than in the case of the metacarpal bone. The large metatarsal bone is even more strongly constructed than the metacarpal. The shell of compact substance is very thick in the middle of the shaft, especially in front and internally. The =small metatarsal= bones are a little longer than the corresponding metacarpals. The =external= (fourth) =metatarsal= is relatively massive, especially in its upper part. The head is large and outstanding, and bears two facets above for the fourth tarsal, and two in front and internally for articulation with the large metatarsal; elsewhere it is roughened for attachment. The =internal= (second) =metatarsal= is much more slender than the outer one, especially in its upper part. The head bears two facets above for the first and second tarsals, and sometimes one for the third tarsal. THE PHALANGES AND SESAMOIDS The axis of the phalanges of the hind limb is about five degrees less oblique than that of the fore limb, and the chief differences in the form and size of the bones are as follows: The =first phalanx= is a little shorter, wider above, and narrower below. The =second phalanx= is narrower and slightly longer. The =third phalanx= is narrower, the angle of inclination of the wall surface is a little (ca. 5 degrees) greater, the sole surface is more concave, and the wings are less prominent and closer together.