THE FORE FEET. 113 



The principal dimensions of the trapezoid bone in two individuals of 

 Binoceras, and one of T'moceras, are as follows : 



Measurements of Left Trapezoid. [Dinoceras mirabile, Xo. 1208.) 



m. 



Greatest vertical extent of trapezoid, .03& 



Length of vertical axis, .022 



Greatest (antero-posterior) diameter, .058 



Transverse diameter, near the middle, ._ .029 



Antero-posterior diameter of proximal articular face, ._ 049 



Transverse diameter of proximal articular face, .027 



Antero-posterior diameter of distal articular face, 05 1 



Transverse diameter of distal articular face, .025 



Measurements of Left Trapezoid. (Dinoceras 7nirabile, 'No. 1230.) 



m. 



Greatest vertical extent of trapezoid, .034 



Length of vertical axis, .023 



Greatest (antero-posterior) diameter, . .067 



Transverse diameter, .035 



Antero-posterior diameter of proximal articular face, .050 



Transverse diameter of proximal articular face, .029 



Antero-posterior diameter of distal articular face, .043 



Transverse diameter of distal articular face, .. .035 



Measurements of Right Trapezoid. {Tinoceras ingens,'No. 1219.) 



m. 



Greatest vertical extent of trapezoid, .038 



Length of vertical axis, _. .025 



Greatest (antero-posterior) diameter, .. .063 



Transverse diameter, near the middle, .033 



Antero-posterior diameter of proximal articular face, .048 



Transverse diameter of proximal articular face, .030 



Antero-posterior diameter of distal articular face, 050 



Transverse diameter of distal articular face, .- - .029 



The MAGxrii. 



(Plate XXXIV. fig-ures 1-6, Plate LIV, figure 1; 

 and woodcuts 121-122, below.) 



The magnum in the Binocerata is proportionally a much smaller bone 

 than in the elephant, and has a much greater difference in the length of 

 the vertical axis in the anterior and posterior parts of the bone, than 

 in that animal. 



