4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



Ulna. — The two nearly complete bones show the amount of differ- 

 ence in size common to male and female in living species in their 

 group. There are 12 additional fragments. These show that the 

 middle section of the wing is decidedly shortened, the larger of the 

 two complete specimens being definitely less than in the female of 

 Anas platyrhynchos. It is interesting also to observe that the two lines 

 of papillae for feather attachment have slight development of the 

 series on the anconal side, which are prominent in birds of strong 

 flight. 



The two fragments of the radius seen are too small to give useful 

 points for comparison. 



Carpometacarpus. — This is represented by i complete bone, 3 others 

 with the main shaft of metacarpal III missing, and 12 additional frag- 

 ments. The complete elements show the slight differences in size that 

 are considered to be due to sex, since they correspond to this distinc- 

 tion in living Anatinae. Compared to Anas platyrhynchos, the longer 

 fossil bones, presumed to be male, are equivalent in length to the 

 female of the living bird. The reduction in length seems to have 

 come in the shafts of metacarpals II and III, as the proximal and 

 distal ends are equal in size to those of the living species. The fossil 

 carpometacarpus has its principal peculiarity in a pronounced con- 

 striction of the anterior end of the shaft of metacarpal III, which 

 at first glance is somewhat confusing as its suggests the form found 

 in the diving ducks. The other contours of the entire bone however 

 are those of species of the Anatinae. 



The slight differences described are those to be anticipated in a 

 species of reduced flight. 



Coracoid. — Ten bones nearly complete and nine fragments illustrate 

 the characters of this bone. The element as a whole is definitely 

 weaker than in the living mallard, as the length is slightly shorter, 

 and the entire bone is less robust. This is noted in the reduction in 

 the brachial tuberosity, the smaller glenoid facet, and the shortened 

 procoracoid, in the head, and in the narrower sternal facet at the 

 opposite end. Only in the coraco-humeral surface is there no notice- 

 able difference. 



Scapula. — The proximal sections of eight scapulae serve to indicate 

 slightly smaller size and relatively more slender shaft, compared to 

 Anas platyrhynchos. 



Miscellaneous. — Additional parts of the skeleton include five frag- 

 ments of the synsacrum, which resemble the similar part in other 

 Anatinae, and are slightly smaller than those of the mallard. 



