124 DINOCERATA. . 



sesamoid bones moved during life. The ridge between these grooves is 

 nearly obsolete in front, but well developed posteriorly. 



The more important measurements of two third metacarpals of 

 Dinoceras are given below. 



Measurements of Third Metacarpal. [Dinoceras mirahile, No. 1208.) 



m. 



Total length of third metacarpal, . .1 14 



Diameters of proximal end, . - r)2-.062 



Diameters of distal end, _. 044-054 



Diameters of shaft, _ .- .031-042 



Antero-posterior diameter of face for second metacarpal, ... .040 



Transverse diameter of face for second metacarpal, _ . .015 



Antero-posterior diameter of face for magnum, _ .056 



Transverse diameter of face for magnum, . . _ .022 



Antero-posterior diameter of face for unciform, ,- _ .050 



Transverse diameter of face for unciform, . 030 



Antero-posterior diameter of face for fourth metacarpal, ...... .050 



Transverse diameter of face for fourth metacarpal, .025 



Diameters of face for phalanx, ._ .0-.'o-.042 



Measurements of Third Metacurpal. [Dinoceras niirabile. No. 1529.) 



m. 



Diamieters of proximal end of third metacarpal, .044-073 



Diameters of shaft, .032-040 



Antero-posterior diameter of face for second metacarpal, .043 



Transverse diameter of face for second metacarpal, . . .014 



Antero-posterior diameter of face for magnum, '.. ... .069 



Transverse diameter of face for magnum, . .. .__. 025 



Antero-posterior diameter of face for unciform (approximate), . . . .055 



Transverse diameter of face for unciform, _ .. .030 



Antero-posterior diameter of face for fourth metacarpal, 059 



Transverse diameter of face for fourth metacarpal, .015-.018 



The Fourth Metacarpal. 



(Plate XXXVI, figures 7-9, and Plate XXXVII, figures 1-3.) 



The fourtli metacarpal in the Dinocerata is a robust bone, like tlie 

 second and tliird of the series. It may be easily distinguished by the 

 broad, sub-triangular, convex articular face, at right angles with the axis of 

 the bone, and covering its entire proximal end. 



