OSTEOLOGY OF BIRDS 



209 



As to the femur in the adult Sage cock, especial attention is invited 

 to its large pneumatic foramen, and its lofty trochanter major. The 

 bone is slightly bowed to the front, and it also exhibits a gentle con- 

 vexity down the inner aspect of the shaft, passing from the caput 

 femoris to the internal condyle. Its popliteal fossa is but moder- 

 ately excavated. The bone varies but little in point of character 

 throughout the gallinaceous series, and the figure of it in Centro- 

 cercus should be compared with the figuce of the femur of G . 

 b a n k i v a given above. 



The patella is never absent in our Gallinae, and is generally of 

 good size. It is chunky in form, and short from above, downward. 

 It accommodates its form, posteriorly, to the rotular channel, having 

 a flat surface superiorly, a rounded border below, and two facets 

 behind, the larger one of which is applied in the articulated limb to 

 the anterior surface of the internal condyle. 



Tibiotarsus and fibula, as well as the tarsometatarsus of Centro- 

 cercus are well shown in plate 9, figures 68 and 69 (Osteology of 

 North American Tctraonidae) . The first two mentioned depart but 

 very slightly from the corresponding bones in the leg of G . 

 bankiva ; the tibiotarsus, however, is about a centimeter (or 

 rather more) longer in the Sage cock. When we come to examine 

 the tarsometatarsus we find that it, too, has the general character 

 of that bone in the wild chicken, but here the question of length is 

 reversed, and the bone in G . bankiva is very considerably 

 longer than it is in the far larger bird, that is in Centrocercus. Nor 

 are spurs developed in the last named species. 



The free os metatarsale accessorium articulates rather high upon 

 the shaft, and as usual, during life, is there attached by its liga- 

 ments. Its distal moiety much resembles in character the same part 

 of any one of the toe joints. These latter are arranged upon the 

 usual plan of 2, 3, 4, 5 to the 1-4 toes respectively. The bony 

 cores of the terminal joints are somewhat decurved, a decurvature 

 that varies both in individuals and in genera. 



All our Gallinae, save Canachites, Lagopus, Centrocercus, and 

 perhaps a few others not examined, develop an osseous lamina ex- 

 tending as a bridge from the back and lower part of the hypotarsus 

 of the tarsometatarsus to merge into the posterior aspect of the 

 shaft near its middle. Turkeys show this character very well, and 

 among the grouse it is well seen in Pediocaetes. 



Very extensive ossification of the tendons of the pelvic limb is to 

 be observed in old specimens of most of our Gallinae, and fre- 

 quently some of the tendons passing to the pinion also ossify. 



