THE FORE FEET. 117 



The Uncifoem. 



(Plate XXXIV, figures 7-12, Plate LIV, figure 1, un ; 

 and woodcuts 123-124, below.) 



The unciform in the Dinocerata is similar, in general shape and 

 proportions, to that of Proboscidians, but is less oblique, and presents three 

 sub-equal articular faces on its distal surface, instead of two, as in 

 the elephant. 



The exterior, or dermal, surface of the bone (Plate XXXIV, figure 7) 

 is moderately roughened and pitted, and is regidarl}- rounded, in the 

 horizontal direction, through an arc but little short of a quadrant. From 

 above downward, the surface is nearly plane. 



The inner surface (figure 8), or that turned toward tlie magnum, 

 is bordered above, in part, and partly below, by a smooth articular 

 face for union with that bone. The amount and disposition of this 

 surface vary in a manner corresponding with the faces for its union 

 with the magnum, as before described. The proximal and anterior 

 portions of this face are the most constant, and may be confluent along 

 the whole margin of the proximal articular face, or mav be interrupted 

 near the middle (number 1195). The proximal part of this face may 

 extend quite across, so as to become confluent with the face for the third 

 metacarpal, and may then, as in the specimen figured, border that face 

 throughout its extent, or it may even fail to reach the lower, or distal, 

 margin of the bone at all (numbers 1509, 1525). 



The posterior, or postero-interior, face of the unciform (figure 9) is 

 quite irregular, and, when not encroached upon by articular faces, is 

 moderately roughened. 



The outer side of the bone (figure 10) is short from above downward, 

 allowing the articular face for the pyramidal to approach tliat for tlie fifth 

 metacarpal, as in the elephant. These faces may even be confluent for a 

 short distance across this surface (number 1211), as in figure 123, below, 

 or may be separated (numbers 1509 and 1525), as in figure 124. 



