158 DINOCERATA. 



The Entocuneiform. 

 (Plate L, figures 1-6, and Plate LIV, figure 2, en.) 



The entocuneiform in the Biriocerata bears but slight resemblance to 

 the corresponding bone in tlie elephant. It is much less elongated in the 

 line of the axis of the foot, and even less so than appears in the general 

 view jf the hind foot on Plate LIV, since the elongation apparent in 

 that figure is, to a great extent, in front of the articular surfaces. These 

 surfaces are, at their nearest points, scarcely more widely separated in the 

 direction of the axis of the foot, than are those of the other cuneiform 

 bones. 



The dermal surface of the bone (Plate L, figure 1) is rough and 

 tuberculated, often much more so than represented in the figure. It is 

 also usually more elongated in the axial direction, in front of the articular 

 surfaces. 



Tlie opposite surface of the bone (figure 3) is flattened, and 

 moderately roughened, and presents a small area only for articulation 

 \\ ith the mesocuneiform. This articular face is confluent with the face 

 for the navicular, and lies along the anterior part of its margin. 



The proximal articular face (figure 5) is of a semi-oval form, and is 

 more or less concave in a direction from the dorsal toward the plantar 

 side of the foot, while transversely it is moderately convex. 



The distal face (figure 6) is much more distinctly saddle-shaped. In 

 some specimens, it is strongly curved forward in the superior region of 

 tlie Ijone, so as to extend through a considerable arch in the direction 

 from the dorsal toward the plantai- side of the foot. Transversely, the 

 articulation is moderately convex throughout. 



The Mesocuneiform. 



(Plate L, figures 7-12.) 



The mesocuneiform is ;i small, somewluit wedge-shaped bone, tapering 



toward its })lantar extremity, and having its shortest dimension in the line 



of the axis of the foot. It is much less oblique than the corresponding 



bone in the elephant, and also less decidedly wedge-shaped. 



