NO. 2 PLEISTOCENE BIRDS, BERMUDA WETMORE 3 



The collection contains four nearly entire tarsometatarsi in addition 

 to the type, with four proximal and three distal ends of others. 



Tibiotarsus. — Fragments of this element include parts of 9 anterior 

 and 16 posterior ends. The more robust have the head, the shaft, 

 and the condyles, particularly the outer one, somewhat heavier than 

 in larger individuals of male platyrhynchos, though the fibular crest 

 is shorter. The range in size is that normal in individual and sexual 

 differences. 



Femur. — This bone is represented by 6 that are nearly complete, 

 with 12 other parts from either end. Four others, all but one com- 

 plete, come from ducklings from two-thirds grown to nearly full size. 

 The material shows the usual size variation found in ducks of the 

 subfamily Anatinae. The fossil bones as a whole indicate heavier 

 form, but slightly shorter length, in comparison with a similar series 

 of ^. platyrhynchos. The more robust size is evident in the proximal 

 end, and at the center of the lower surface of the shaft which is 

 more broadly rounded, less angular. The popliteal area appears 

 broader. 



Humerus. — Six nearly complete bones, and 20 fragments are re- 

 ferred to this species. In form these are quite uniform, with the 

 dififerences in size those common between male and female. However, 

 it is to be noted that the larger group, presumed to come from male 

 individuals, have the dimensions of female Anas platyrhynchos, and 

 are thus definitely smaller than that species. The head of the bone 

 is reduced in size, and is less undercut on the anconal aspect, so that 

 there is no overhang above the upper end of the shaft. The external 

 outhne of the deltoid crest is more rounded, less angular, and the 

 external tuberosity, viewed from the upper side, is supported on a 

 narrower base. The elevated line of the attachment of the latissimus 

 dorsi anterioris is decidedly shortened, but at the same time is pro- 

 duced as a sharp ridge that is more prominent than in any of the 

 modern species of ducks that I have seen. At the distal end the 

 external condyle is reduced, and the brachial depression is shallower, 

 with less definite outline. 



The impression from these comparisons is that the bird was one of 

 sedentary habit and weakened powers of flight compared to the strong- 

 flying, living species with which it has been compared. In support of 

 this supposition I find that the humerus of this fossil species of 

 Bermuda, in those points in which differences have been described 

 above, agrees rather closely with the same bone in living Anas laysan- 

 ensis Rothschild, which lives around the lagoon on Laysan Island 

 in the Hawaiian Wildlife Refuge, where it is completely sedentary. 



