326 



ANATID.E. 



primary quill-feathers of equal length, and the longest in 

 the wing. 



The female differs from the male in having the plumage 

 of dull brown, which is lightest in colour about the cheeks 

 and under surface of the body ; the beak dark olive ; the 

 feet greyish-brown. According to the descriptions given, 

 the trachea of the Surf Scoter resembles that of the Velvet 

 Scoter as represented at page 316. 



The vignette below represents the difference in the ex- 

 tent of the membrane depending from the hind toe of the 

 two divisions of 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. 



