266 



DUCK GROUP 



rudimentary after-shafts, and there arc no featherless tracts on the 

 neck. The three front-toes are (in all British forms completely 

 united by webs, and the short hind-toe is elevated above the level of 

 the others. The close compact plumaLje, [general build, and waddling 

 gait of most representatives of the group arc too well known to need 

 more than passing mention. To these casilj- recogni.sed external 

 characteristics it may be added that the " mcrr\— thought " bone 

 (furcula) is U-shaped in place of the more usual \'-shape, that the 



large breast -bone has a 

 single shallow notch 

 (sometimes converted into 

 a jicrforation) on each 

 side of its hind border, 

 and that the lower part of 

 the intestine is furnished 

 with a pair of relatively 

 large blind appendages 

 (cxca). To correspond 

 with the plates on the 

 inner surface of the upper 

 half of the beak, the sides 

 ^^M' ^ ^^^^M of the tongue arc furnished 



^^ ^^HESI^B with a series of ridges 



m^^rmm^ *- "'% '^"'-^ grooves, so that the 



C^ " ..,^ 7:"^^^^_^ ^tffeT'' t^ margins of the mouth 



form a most efficient 

 straining apparatus, 

 whereby the solid food is 

 separated from the water. 

 All members of the 

 group, which includes 

 ducks, swans, geese, and mergansers, associate in pairs during the breed- 

 ing-season, although man\- of them collect in large flocks for the winter. 

 Although a few foreign species habituall}- j^erch and build in trees, the 

 great majority make their nests as a rule near the water's edge, employ- 

 ing rushes or grass in their construction, and lining them with down 

 jilucked from the breast of the female, and also using this material as a 

 packing for the eggs. The latter are numerous and uniformly coloured ; 

 their tint varying from white through cream-colour and buff to pale 

 sea-green, but their shape being alwaj^s oval or ellijitical. On emerging 

 from the shell, the \-oung are fully clothed with down, and are at once 



\VH(X)I'KK SWAN. 



