54 THE AMERICAN BEAVER. 



The femur is broad and very strong, 4" 10"' in 

 length. Besides the two trochanters, there is a prom- 

 inent process on the outer margin, below the middle 

 of the bone, from which a sharp edge extends above 

 and below; a deep pit exists on the under side of the 

 great trochanter. 



The tibia is 5" 25'" long, triangular above. Its body 

 is excavated on each side of the posterior angle ; be- 

 low it is rounded, with but small development of the 

 malleolar process. 



The fibula forms a strong outer malleolar process 

 in close apposition to the astragalus. It is attached 

 for 1" 25'" to the lower end of the tibia, and after the 

 epiphyses become consolidated the union is by anchy- 

 losis. The upper end of the fibula lies behind the 

 tibia, and has a hamular process pointing outwardly 

 and downward, which gives attachment to a strong 

 ligament that extends from the lower part of the bone 

 and passes from the process in question to the femur, 

 forming an outer lateral ligament to the knee-joint. 



The patella is subtriangular in form with the base 

 above. 



The plane of the foot is oblique with respect to the 

 leg, requiring the feet to approximate to rest on a 

 level surface. The tarsal bones are 8 in number. 

 The astragalus requires no particular description. 

 The calcaneum is flattened obliquely on its upper and 

 under surfaces, and projects backward 84'" It articu- 

 lates with the astragalus and the cuboid. The sca- 

 phoid has a neck and a rounded head which is seen 

 in the bottom of the foot. A nameless bone, subcon- 

 ical in shape, which is properly an appendage to the 

 scaphoid, articulates with the astragalus on the inside 



