454 RICHARD S. LULL 



as the shaft would not have been sufficiently rigid to withstand 

 springing, had the thigh been flexed. Another interesting feature 

 is the absence of a third trochanter — a character given by Marsh in 

 his definition of the genus Megacerops. There is a ridge on the outer 

 side of the femur continuous above with the great trochanter, which 

 probably represents the vestige of the third. 

 The measurements are: 



Length --------- 0.785 



Width of proximal end - - - - - - - 236 



Width of distal end ------- . 204 



Width of mid shaft - - - - - - - .117 



Depth of mid shaft ------- . 060 



The tibia. — The general form of this bone is well shown in the 

 figure, and calls for no special comment. 

 The measurements of the tibia are : 



Length ---------- 0.446 



Width of proximal end ------- . 200 



Depth of proximal end ------- .132 



Width of mid shaft ------- . 08c 



Depth of mid shaft - - - - - .- - - .077 



The fibula is quite slender with expanded articular extremities. 

 Length ---------- 0.395 



The pes. — The general proportions are in keeping with those of 

 the manus. All of the tarsal elements are represented, with the 

 exception of the entocuneiform which is entirely lacking. 



The calcaneum. — The tuberosity is rather long and very rugous 

 at its distal end, and with a much- flattened shaft which is about one- 

 half as wide as long. The calcaneum bears facets for articulation 

 with the cuboid, the astragalus, and on its upper outer face a small 

 one for the articulation with the fibula. 



The calcaneo-astragalar facet is somewhat saddle-shaped, its fore- 

 and-aft axis being a reversed curve, first concave, then convex. The 

 sustentacular facet, however, is deeply concave, the transverse axis 

 curving through an arc of 90 , while the fore and aft axis is straight. 

 Below there is but one facet, the calcaneo-cuboid, somewhat semilunar 

 in shape, extending about half the width of the bone. Except for the 

 articulation with the fibula, there is little evidence of movement 

 between the calcaneum and the adjoining bones. 



