1 88 Shufeldt, Material for a Study of the Megapodiidce. [,,f ")"„. 



and dilated ends, while each one of the outer pair is very large, 

 broad, and thin, the upper free end of either one being produced 

 to a point anteriorly as well aS posteriorly (fig. 42). 



The costal borders are deeply excavated between the articular 

 facets, and honeycombed in various directions by pneumatic 

 foramina. 



As a matter of fact, most all of the trunk skeleton is pneumatic, 

 the coccygeal vertebra; and pygostyle being the principal ex- 

 ceptions. 



The Pectoral Limb (Plate XVI., figs. 32 and 35). — ^This mound- 

 bird has a powerful skeleton with respect to its limbs, the long 

 bones being lengthy and very strong ; in other words, it is a big- 

 boned bird, in so far as its pectoral and pelvic limbs are concerned. 



The humerus has a length of about 8.7 cms., and is possessed 

 of a stout shaft, somewhat compressed in the plane of its expanded 

 proximal end, and to some degree exhibiting the usual sigmoid 

 curve. The radial crest is very low, thick, and rather short. 

 Both the head and distal tubercles are largely developed, and the 

 valley between the head and the ulnar tuberosity unusually deep. 

 On the other hand, the pneumatic fossa is shallow, though within 

 the deeper elliptical one at the centre of the fossa are many 

 pneumatic openings. 



In the antibrachium the ulna has a length of 9.7 cms., and is an 

 unusually stout and much' curved bone. There are seven fairly 

 well marked papilla; down its shaft for the quill-butts of the 

 secondary feathers of the wing. The radius is shorter than the 

 ulna, being but 8.9 cms. in length ; moreover, it is quite straight, 

 and its shaft has not more than one-third the calibre of the shaft 

 of its companion bone. 



The " interosseous space " between these bones of the fore arm 

 is great, but it is entirely due to the unusual amount of curvature 

 of the ulna (figs. 32 and 35). 



Radiale and ulnare of the carpus present their unusual ornithic 

 characters ,as found in representatives of this group of birds. 

 Rather bulky in proportions, they make the ordinary articulations 

 with the bones of the antibrachium and the main bone of manus. 

 This latter possesses an extreme length of 4.9 cms. Its main 

 shaft is stout, and inclined to be curved along its anterior face, 

 the slenderer companion metacarpal (III.) being still more curved. 

 Both are considerably broadened and flattened below or at their 

 distal extremities. Pollex digit is long and pointed (1.9 cms.), 

 the distal phalanx of the index digit being shorter, while that of 

 medius is a short, peg-like bone, only 7 milhmeters in length. 



The Pelvic Limb (figs. 37 and 41). — Distally, the femur is much 

 expanded antero-posteriorly, the great trochanterian ridge rising 

 above the smooth, broad summit of the bone. Caput femoris is 

 rather small and quite globular, the pit for the ligamentum teres 

 being somewhat diffuse. There are no evidences whatever of a 

 trochanter minor, and the smooth, subcylindrical shaft of the 

 bone is quite straight.. Linea aspera is fairly well marked, as are 



