( 618 ) 



WOOD DUCK. 



Anas sponsa, Linn. 



PLATE CCVI. Vol. III. p. 52. 



Dr Bachman, who has kept a male of this species several years, 

 states that after moulting he is for six weeks of a plain colour, like the 

 young males, and the feathers gradually assume their bright tints. 



Male. Width of mouth 8 twelfths ; the upper mandible is widely 

 concave, with a prominent line, on which are a few papillas ; there are 

 about 30 lamella^ on each side of the upper mandible, of which only five 

 about the middle project beyond the margin, on the edge of the lower 

 are 35. The tongue is fleshy, 1 inch 5 twelfths long, papillate at the 

 base, contracted toward the middle, the edges thin and lamellate, the 

 tip semicircular, thin, and horny. (Esophagus 8| inches long, its width 

 uniformly 10 twelfths; the proventriculus 4 inches in breadth. The sto- 

 mach is a very large muscular gizzard of a transversely elliptical form, 

 placed obliquely, 1 .inch 5 twelfths long, 1 inch 8^ twelfths broad ; the 

 lateral muscles very thick, and forming a singularly thin edge ; the ten- 

 dons covering the whole surface ; the left muscle 7 twelfths thick, the 

 right 8 twelfths ; the epithelium very thick, dense, with two elliptical 

 grinding surfaces. Proventricular belt 1 inch 5 twelfths in breadth. 

 Lobes of the liver 1 inch 8 twelfths, and 2 inches 8 twelfths long. In- 

 testine 37 inches long, for a short space at the commencement, its width 

 is 4 twelfths, but presently contracts to 2\ twelfths, and ultimately to 

 2 twelfths, being more slender than that of any other species of this 

 family examined. The coeca are 2\ inches long, 1| twelfth in width, 

 and placed at the distance of 34 inches from the extremity. 



Trachea 65 inches long, much flattened, of the uniform width of 3 

 twelfths ; its rings rather firm, 120 in number, of which about 15 at the 

 lower part are extremely narrow and distant in front. There is an ir- 

 regular transverse bony ovate dilatation, 10 twelfths in breadth, 6 

 twelfths in length, with its greatest protuberance to the left side, as is 

 usual. Bronchi of moderate length, the left of 28, the right of 30 half 

 rings. There are no inferior laryngeal muscles, and both the sterno- 

 tracheals come off on the right side, the left one winding behind the 

 right end of the tympanum. 



