258 



GADWALL DUCK. 



the male, but the speculum fainter. Tail-feathers and their coverts dusky, 

 laterally obliquely indented with pale brownish-red, and margined with 

 reddish-white. 



Length to end of tail 19^ inches, to end of wings lSf, to end of claws 

 19^; extent of wings 31; wing from flexure 8i; tail 3f; tarsus Iff; middle 

 toe Iff, its claw r j S . 



In a male, the roof of the mouth is deeply concave, with a prominent 

 median ridge, and oblique grooves toward the end. The tongue is 1 inch 

 10 twelfths long, fleshy, with a deep longitudinal groove, two lateral series 

 of filaments, and a thin broadly rounded tip, as in other Ducks. The oesopha- 

 gus, a, b, is 10^ inches long, 

 5 twelfths in diameter for 

 about four inches, then en- 

 larged to 10 twelfths, and 

 again contracted as it enters 

 the thorax. The proven- 

 triculus, b b, is 1 inch and 

 2 twelfths long, its greatest 

 diameter 8 twelfths. The 

 stomach, c d e, is a very 

 large and powerful gizzard, 

 of an elliptical form, com- 

 pressed, 1 inch and 9 

 twelfths long, 2 inches in 

 its greatest breadth, or in 

 the direction of the lateral 

 muscles, of which the right, 

 c, is 10 twelfths thick, the 

 left, d, 9 twelfths. The 

 epithelium is thick and 

 rugous; much thickened 

 and forming two roundish, 

 flat or slightly concave 

 grinding surfaces, opposite 

 the muscles. The intestine, 

 efg, is 6 feet 10 inches 

 long, wide, its diameter for 

 2 feet being 4^ twelfths, 

 towards the rectum enlarg- 

 ing to 6 twelfths. It forms 

 first a very long duodenal 



