333 THE THIGH AND LEG. [CH. XVIM. 



approaching in some degree to the rotation often permitted 

 between the radius and ulna. 



In the MONOTREMATA the femur (Fig. 1 2 1,/) is of very 

 remarkable form, being short, flattened from before back- 

 wards, narrow in the middle of the shaft, and very broad 

 at each end ; the trochanters are both well developed, and 

 the head placed between them on a very short neck, and 

 with its axis directed quite towards the anterior or dorsal 

 aspect of the bone. The fibula (_/') is large and straight : 

 it has a broad flattened process, completed by an epiphysis, 

 projecting from the upper extremity above the point of articu- 

 lation with the tibia, much resembling the olecranon of the 

 fore limb. The tibia (/) is strongly curved in Ornithorhynchus. 

 but straight in Echidna . In both genera the patella (/) is 

 well developed. 



