250 



ANATID.E. 



greater wing-coverts black ; wing primaries brownish-black ; 

 secondaries white, forming the speculum, and tipped with 

 black ; rump and upper tail-coverts nearly black ; tail-feathers 

 dark brownish-black ; the sides below the wings, and the 

 flanks, covered with fine grey lines, on a ground of white : 

 lower part of breast and the belly mottled with pale greyish- 

 brown and white ; vent dark grey, almost as black as the 

 under tail-coverts ; feet like the beak, much smaller than 

 these parts in the true Scaup, and darker in colour, being of 

 a more uniform bluish-black. 



In the figures given, great care has been taken to present 

 the true relative appearance of the two birds. 



I only know of this one example found in England, which 

 was purchased in Leadenhall market a few winters since. 

 The form of the trachea is unknown to me, and not possess- 

 ing any measurements taken before the bird was preserved, I 

 refrain from mentioning those which may not exist in a state 

 of nature. 



The vignette below represents the difference in the extent 

 of the membrane depending from the hind toe of the two 

 divisions of the true ducks ; that on the left side belongs to 

 the first division, or surface-feeding Ducks ; that on the right 

 to the second division, the oceanic, or Diving-Ducks. 



