NO. 2 PLEISTOCENE BIRDS, BERMUDA — WETMORE 5 



Basal phalanges of three anterior toes equal in size those of male 

 Anas platyrhynchos, so that the foot was large. 



Discussion. — In this examination of the available parts of the skele- 

 ton, comparisons have been made with the modern mallard, Anas 

 platyrhynchos Linnaeus, as the type species of the genus. In sum- 

 mary, the fossil appears to have been a species with the body size of 

 a medium or small mallard, but with heavier legs, and definitely 

 smaller wings. It seems, therefore, to have been a sedentary bird, 

 active in swimming and walking, but with slight necessity for pro- 

 longed use of the wings, since so far as known it had no resident 

 predators. The general condition resembles what I found in study of 

 the living Laysan duck, Anas laysanensis Rothschild, restricted to tiny 

 Laysan, an island in the Hawaiian Wildlife Reservation that is only 

 one and three-quarters miles in length. The ducks are restricted to 

 the central salt-water lake where they range mainly around fresh- 

 water seepages along the lagoon shore. When I approached they 

 waddled slowly away, and took to wing rather heavily only when hard 

 pressed. On Laysan, as on the Bermudas, there are no active preda- 

 tors so that strength in escape flight was not required. Some of the 

 ducks flew fairly well over the lagoon, but others were exhausted 

 after a flight of 125 yards so that I ran them down on foot and caught 

 them by hand. It may be thought that the Bermuda duck was of 

 similar habit. 



The osteological differences that separate the fossil from living 

 Anatinae are considerable, and may warrant its designation in a dis- 

 tinct genus, particularly since it appears to have no close relatives, 

 either living or fossil. Most of the fossil ducks that may be related 

 have been described from fragmentary bones, so that their full 

 characters are unknown. Because of this it has seemed best for the 

 present to treat the bird of Bermuda as a species of the genus Anas 

 in the broad sense, at least until the osteology of all of the living 

 kinds included in the subfamily is more fully known. 



MEASUREMENTS OF Anas pachyscclus (in millimeters) 



Tarsometatarsus : 

 Length, 44.5, 44.9, 45-6, 45-7, 45-7, 45-8, 45-9, 45-9, 46.0, 46.2, 46.2, 48.2. 

 Transverse breadth of anterior end, 9.5, lo.o, lo.i, lo.i, 10.2, 10.2, 10.5. 

 Transverse breadth of shaft near center, 4.4, 4.5, 4.5, 4.6, 4.7, 4.7, 4.7, 4.9, 5.0, 



5-1. 5-2, 5-3, 5.3- 

 Transverse breadth of distal end, 10.8, 10.8, 10.9, 10.9, ll.l, 11.3, 11.5, 11.8. 

 Tibiotarsus : 



Smallest transverse breadth of shaft, 3.8, 4.0, 4.2, 4.3, 4.3, 4.4, 4.4, 4.5, 4.5, 4.5, 



4.6, 4.6, 4-7, 4-7, 4-7. 



