230 Shufeldt, Osteology of Cereopsis novcB-hollandicB . [isf A^rii 



In Branta, the foiirchette is non-pneumatic, while in Olor it is 

 much modified in its morphology at the lower part of the arch, in 

 order to accommodate the passage of the trachea to and from 

 the tracheal chamber of the sternum in members of that genus. 



The Appendicular Skeleton. 



The Pectoral Limb (fig. 22, Plate XXXI.) — In this Goose the 

 skeleton of the wing presents every indication of powerful develop- 

 ment, suggesting at once a bird endowed with the maximum 

 capacity of flight. 



The humerus presents the usual sigmoid curves from proximal 

 to distal end, though in no marked degree. It has an extreme 

 length of about 171 millimetres, and is completely pneumatic, 

 the air gaining access to the interior of the bone through a large 

 elliptical foramen situated, as usual, in the pneumatic fossa on 

 the anconal side of the bone, beneath the eaves of the ulnar 

 tuberosity. The lower boundary of this is extended as a thin, 

 sharp crest or border, which is lost upon the shaft not far from 

 the pneumatic opening [crista inferior). Caput humeri is large 

 and smooth, being separated from the ulnar tuberosity by a well- 

 marked incisura capitis, which gives especial prominence to the 

 tuber cidum internum . 



There is a very conspicuous radial crest, which has a somewhat 

 thickened, convex border. It is bent over so far palmad as to be 

 almost perpendicular to the palmar aspect of the shaft, it being 

 extended down the latter to a point about at the junction of the 

 proximal and middle thirds. At its widest part the proximal 

 extremity of the humerus measures about 33 millimetres. The 

 middle third of its shaft is subcylindrical in form, and very smooth. 



At the distal extremity we are to note the usual radial and 

 ulnar tubercles for articulation with the bones of the forearm, 

 and proximad to them a fairly well marked depression indicating 

 the site for the insertion of the brachialis anticus muscle. Prof. 

 Fiirbringer designates this depression as the fovea supra- 

 trochlearis ventralis des Humerus in the common Goose, and states 

 that the brachialis inferior muscle arises there, which statement 

 is also made by Dr. Gadow in Newton's " Dictionary of Birds " 



(P- 439)- 



The ectepicondylar process is but feebly pronounced at this 

 distal end of the humerus in Cereopsis, and the same may be said 

 for the entepicondylar one on the other side of the bone. 



In Chen hyperboreus the humerus is somewhat smaller than the 

 bone in this Cape Barren Goose, but the characters are identical. 



Passing to the ulna, we find it to have a length of some 173 mm., 

 the radius being but a trifle shorter. Down the palmar aspect 

 of the ulnar shaft there is a fairly distinct raised line, shghtly 

 broken at nearly regular intervals by minute elevations, averaging 

 some II mm. apart. This line is quite straight, and indicates 

 where the quill-butts of the secondary feathers are inserted in life. 

 Proximally, the head of the ulna is very large, and the big shaft 



