77 



column or buttress along the outside of a large and deep cavity before it 

 subsides into the level of the shaft. Viewed from the outer side, the 

 broad external rugged surface of the great trochanter hides the rest of 

 the proximal third of the femur from view, so much does it surpass that 

 and every other part of the bone in antero-posterior diameter. It gra- 

 dually contracts to form the strong external ridge which descends, inter- 

 rupted by only a slight emargination to be continued into that which 

 surmounts the external condyle. 



The anterior production of the great trochanter is narrower and more 

 rugged than the posterior one ; it is also flattened and separated by a 

 ridge from the outer convex surface of the process, with which it is placed 

 nearly at right angles : the external border of the shaft of the femur 

 seems to be more immediately continued from the lower angle of the 

 anterior surface of the trochanter, and is slightly bent forwards, bounding 

 the concavity which extends along the outer third of the anterior surface 

 of the shaft of the femur. The small trochanter is a vertically oval de- 

 pressed tuberosity, situated directly upon the inner border of the femur 

 two inches below the head, from which it is separated by a smooth and 

 shallow concavity. The posterior intertrochanterian space is smooth 

 and convex, except where it sinks into the cavity which partly under- 

 mines the posterior columnar prominence of the great trochanter. 



Purchased, 



442. The right tibia of the Mylodon robustm : the proximal articulation for 

 the fibula and the surface for the outer condyle of the femur are broken 

 off: the articular depression for the inner condyle is elliptical and occu- 

 pies the whole of the corresponding division of the head of the tibia : a 

 small portion of its anterior part is convex and rises to a slight eminence 

 near the middle excavation, the rest of the surface is slightly concave. 



The shaft of the tibia swells out anteriorly into irregular rough con- 

 vexities, forms a smoother border about the inner articular surface, and 

 falls in on every side to the lower third of the shaft, at the beginning of 

 which the bone presents its smallest circumference. The anterior sur- 

 face below the proximal rough swelling is flattened, and meets the 



