320 TllK WASATCH lATNA. 



tlie anterior face, inclining to an angle of 40^. Its interior extremity is 

 continued to a rather acute process, which is separated by an open notch 

 from the btise of the malleolus. This carries the tendons of the flexor longus 

 diil'donim and tibialis posticus muscles. The head of the fibula j)rojects con- 

 siderably external to its tibial facet, the resulting section being ti'apezoidal, 

 apj)roaching triangular. The posterior face of the head is gently concave 

 and is surmounted by a low free rim. A ridge extending forwards from this 

 gives the proximal end of the head a roof-shaped form. 



The posterior groove of the astragalus is wide. Its internal bounding 

 angle is prominent, forming an oljliquely descending tuberosity. The ex- 

 ternal bounding tuberosity is not so prominent. The anterior angle bound- 

 ing the external calcaneal condyle is not more prominent, differing thus dis- 

 tinctly from that of Mesonyx ossifragus. The lateral trochlear angles of 

 the astragalus are obtuse, especially the internal. 'Jhe inner base of this 

 bone has an open median notch. When the calcaneum is in position it is 

 evident that the animal walked partly on its external side. This is bounded 

 externally in front of the external condyle by a horizontal crest. The cu- 

 boid facet only covers the external two-thirds of the distal extremity of the 

 calcaneum. The internal third, however, retreats rapidly posteriorly in- 

 wards. The very oblique calcaneal fac* of the cuboid, already described, 

 is deeply notched externally by the proximal part of the groove for the 

 flexor digitorum tendon. This groove forms a quarter of a circle, passing 

 downwards, outwards, and backwards. The distal face of the cuboid is 

 concave and is undivided. The entocuneiform facet of the navicular is 

 situate more than its width away from the internal margin of the bone. 

 The mesocuneiform is wide. The ectocuneiform is narrower than the latter, 

 and bevels the external extremity of the navicular, thus looking towards the 



cuboid. 



Measurements of posterior limb. 



it. 



Dmmeters of proximal endof tibia 5 '■""' ""'' ''^' ^''"^ «■•««* ^^ 



I tnmsvorso 031 



Diameters ofdistal end oftibia I '■"""'""•"'■' "1^ 



( tr.'iiisvcrso 034 



Foru and aft dianioti-r of proximal end of fibula 017 



Total li-ngtli of a.stniKaliiH 0:S 



I ant(!ropoHt4;riur(;xtemaIly 0155 



DNimctiTsiif irocIili'iK^ vt-rlioal externally 0145 



( trauBvereo 017 



