52 R. W. SHUFELDT, 
they are always completely non-pneumatic, as they are among the 
Anatinae generally. In Chen, the ulna may be pneumatic, though 
the foramina at its proximal end are very winute. Then, too, the 
radius and carpo-metacarpus appear to be so in this species, though 
I have failed to locate the foramina. BDranta canadensis has a pneu- 
matic ulna, and the radius and carpo-metacarpus, I believe, also 
enjoy that condition, though I have succeeded only, in the case of 
the latter bone, in locating a single minute air-hole It is at 
the base of the fossa on the palmar side of the head, posterior 
to the there-existing process formed by the united first distal 
carpal. 
Among the Cygninae, as far as I have examined them, the 
humerus is the only bone of the pectoral limb that is pneumatic, — 
agreeing with the Anatinae in this respect. 
In Dendrocygna autumnalis (454) it has an extreme length of 
118 mm. Its shaft is moderately concaved toward theinterosseous 
space, the arc being most evident for its proximal third. The 
“quill-butts” for the insertion of the secondary wing-feathers are but 
feebly developed down the palmar aspect of the rather stout sub- 
cylindrical shaft. At the extremities of the latter, we find the usual 
enlargements and articular cavities, or other surfaces, for the humerus 
and radius proximally, and the ulnare carpal distally. 
From end to end, the smooth, somewhat slender shaft of the 
radiusis nearly straight, while its extremities offer the usual articular 
surfaces and facets for the humerus and ulna proximally, and for 
the radiale carpal distally. At its widest part, which is at the 
proximal thirds of the bones of the forearm, the interosseous space, 
at its widest interval, measures 7 mm. 
From what has gone before it will be noted that the bones of 
the antibrachium are, in Dendrocygna, but slightly longer than the 
humerus. In Olor columbianus, the ulna and the humerus are 
about of equal length, and this is likewise the case in Chen hyper- 
boreus nivalis and nearly so in Cereopsis; while in Polystieta stelleri, 
Aix sponsa, Chenonetta jubata, Hymenolaemus malacorhynchus, and in 
the Merginae the humerus is, as is probably the case in many 
other ducks, considerably longer than the ulna in any particular 
wing of any species. Presenting nothing worthy of especial note, 
the ulnare and radiale of the carpus have the usual character 
of those bones among the Anseres generally. Doubtless, were 
they :to be critically compared, with respect to comparative pro- 
