THE FORE FEET. 109 



3reasurements of Left Pyramidnl. [Tinoceras lugens. No. 1577.) 



m. 



Greatest length of longitudinal axis of jiyramidal, __ _ .050 



Greatest diameter of bone, .113 



Least transverse diameter, . .009 



Greatest diameter of ulnar articular surface, 092 



Antero-posterior diameter of ulnar articular surf :ice, .062 



Greatest diameter of articular face for unciform, .080 



Antero-posterior di.ameter of articular face for unciform, 066 



The Pisiform. (Plate XXXII, figures 7-12.) 



The pisiform in the D'ntO(erat(( is a short, stout hone, pre.senting, as 

 usual, two continent articular faces, one for the ulna, and the second for 

 the pyramidal. 



Plate XXXII, figure 7, represents the surface of the pisiform seen 

 from the side of the skeleton, when the bone is in its natural position, 

 except that the long axis has been placed in a vertical, instead of an 

 oblique, position. Neither of the articular faces can be seen in this figure. 



The inner side of the bone, or that turned toward the pyramidal 

 (figure 8), shows, at its proximal end, a large and somewhat triangular face, 

 flattened, or slightly concave or convex, and extending, in the specimen 

 figured, over more than half the length of the bone, but, in some specimens, 

 it is proportionally shortei". 



Figure 9, which gives the view opposite to that in figure 7, shows 

 this articular face, seen obliquely. 



The proximal end of the bone (figure 11) is nearlv covered by a 

 triangular articular face for union with the ulna. This face, in the 

 specimen figured, is flat in one direction, and distinctly convex in the 

 other, but another specimen of the same bone has this face distinctly 

 convex in both directions. 



Distally, the pisiform is strongly roughened and tuberculated, with 

 the end rounded, as shown in figure 12. 



The pi'inclpal measurements of two specimens of the pisiform bone in 

 Dinoceras mirabile are given below. 



