386 



FAMILY XL.— MERGING. MERGANSERS. 



Bill rather long, straight, rather slender but strong, tapering, higher than 

 broad at the base, nearly cylindrical toward the end; upper mandible with 

 the dorsal outline sloping gently to the middle, then straight, along the 

 unguis suddenly decurved; the ridge broad and flattened at the base, then 

 convex, the sides sloping, toward the end convex, the edges serrate internally 

 with oblique dentiform lamellae, the unguis oblong, much curved, abruptly 

 rounded at the end; nasal groove elongated, covered by the soft skin of the 

 bill; lower mandible with the angle very narrow and extended to the unguis, 

 which is obovate, the sides nearly erect, with a long narrow groove, the 

 edges internally serrate, the unguis convex, thick-edged. Head rather large, 

 compressed, oblong; neck of moderate length; body full, depressed, rather 

 elongated. Feet placed far behind, stout; tibia bare for a short space; tarsus 

 very short, compressed, anteriorly covered with small sc#tella, and another 

 series on the lower half externally. Hind toe very small, with an inferior 

 free membrane; anterior toes half as long again as the tarsus, second shorter 

 than the fourth, which is almost as long as the third, all scutellate, and con- 

 nected by anteriorly concave webs. Claws rather small, moderately arched, 

 compressed, acute. Plumage moderately full, dense, soft, glossy, blended 

 beneath. Wings of moderate breadth, convex, acute; inner secondaries 

 elongated and tapering. Tail short, much rounded, of more than twelve 

 feathers. Upper mandible with an internal series of small papillae or laminae 

 on each side, besides those on the margin. Tongue long, fleshy, emarginate 

 and papillate at the base, tapering, with a double row of slender reversed 

 papillae along the upper surface, and two lateral series of filaments on each 

 side, the tip lacerated; oesophagus very wide, of nearly uniform diameter; 

 stomach a strong gizzard of moderate or small size, with the lateral muscles 

 thick; the epithelium dense and longitudinally rugous; intestine long, rather 

 narrow; cceca rather long; cloaca globular. Trachea with one or two 

 extensive dilatations, besides the enormously developed tympanum at the 

 bifurcation; no inferior laryngeal muscles. Nest on the ground, or in hollow 

 trees. Eggs numerous. 



Gexus I.— MERGUS, Linn. MERGANSER. 

 Character as above. 



