Diameters M.i^''"**'''?''^*^"''"' ^^^ 



_,. . ,,.., anteroposterior 012 



Diameters M. " ■" '^ 



736 THE EOCENE FAUNA. 



t transverse 009 



( transverse . 010 



_. , r- ■ i. V (anteroposterior OlO 



Diameters of incisor at base < 



( transverse 007 



Length of incisor exposed, posterior face 020 



Depth of ramus at middle of diastema 024 



Depth of ramus at middle of M. i 033 



Width of inferior face of ramus below posterior edge of M. ii 022 



An anterior caudal vertebra is short anteroposteriorly, and its long- 

 axis is oblique to the vertical axis, as in the cervical vertebrae of many ver- 

 tebrates. It is flat below, and their bases indicate wide flat diapophyses 

 The articular faces of the centra are both concave. Neural canal small; 



neural spine distinct. 



Measurements caudal vertebra. 



M. 



Length below 0.014 



Depth centrum posteriorly 016 



Width centrum posteriorly 019 



Elevation of neural arch 012 



The astragalus is characterized by its relative width transversely, the 

 small concavity of the trochlea, and the small head. The inner posterior 

 angle is produced flattened and rounded, as viewed from above. The pos- 

 terior and lateral internal fossae are well marked. The external or fibular 

 face is not longer than deep, and is nearly vertical. Its anterior inferior 

 angle is little produced, but is separated from the edge of the trochlea by 

 deep vertical faces both laterally and anteriorly. The navicular face is 

 wider than deep, is convex in vertical section, and a little convex in trans- 

 verse section. The cuboid facet is anteroposterior, looking outwards, and 

 is about half the width, and the same depth, as the navicular. It is con- 

 tinuous inferiorly with the sustentacular facet. The latter is considerably 

 overhung by the internal edge of the bone. From the forward divergent 

 direction of the condyloid calcaneal facet of the astragalus, it is evident 

 that the cuboid is a large bone, and that the external two toes are dispro- 

 portionately large. 



Measurements of astragalus. 



M. 



Totallength 0.027 



Total width 028 



„. i i ui (transverse 017 



Diameters trochlea < . „ 



I anteroposterior externally .017 



