346 AMERICAN SCOTER DUCK. 



other species in having the sides of the unguis narrowed, and the orange 

 patch on the upper mandible less extended beyond the nostrils, and destitute 

 of the median black line and lateral streak. There is less difference in the 

 colour of the plumage however, than has been represented; for adult males 

 of this species are not sooty-brown above, but deep black. 



An adult male, from Dr. T. M. Brewer, of Boston. The roof of the 

 mouth is very concave and broad, with a median ridge, on which there are 

 six papillae towards the base. There are about 25 large lamella? on each side 

 of the upper mandible, besides a number of smaller ones anteriorly; about 

 40 on each side of the lower mandible. The tongue is 1 inch 10 twelfths 

 long, its greatest breadth 9|- twelfths; the papillae at the base long and 

 pointed, the sides furnished with two rows of bristles, the tip thin-edged and 

 rounded. The aperture of the glottis, and that of the posterior nares, are 

 beset with minute papillae. The oesophagus is 10^ inches long, of moderate 

 width, its greatest diameter being 10 twelfths; that of the proventriculus 1 

 inch. The stomach is a strong gizzard of moderate size, 1^- inches in length, 

 and 1 inch 10 twelfths in breadth; its left lateral muscle 10 twelfths in thick- 

 ness, the other 9 twelfths; the epithelium tough, dense, forming two round- 

 ish slightly concave grinding surfaces. The proventricular glandules, which 

 are rather small, of a roundish form, 1^- twelfths long, form a belt li inches 

 in breadth. The contents of the stomach are particles of quartz. The 

 intestine is 4 feet 11 inches long, rather wide, its diameter pretty uniform, 

 and about 4|- twelfths. The coeca, which come off at the distance of 4 inches 

 from the extremity of the gut, are S inches in length, 2\ twelfths in their 

 greatest diameter, with the extremity obtuse. 



The trachea is 6i inches long, flattened, its breadth 5 twelfths, contracting 

 at the lower part to 4 twelfths. Its rings are but partially ossified, being 

 cartilaginous at the back part. It is entirely destitute of those remarkable 

 dilatations seen on the trachea of Fuligula perspicillata and F. fusca. 

 The bronchi, however, are of very large size, being 1 inch 4 twelfths long, 

 their greatest breadth ^ inch. The inferior larynx is very small, being only 

 3| twelfths in breadth, in which respect it differs from that of most other 

 male Ducks. It is indeed very remarkable that this species, so nearly allied 

 to the Velvet and Surf Ducks, should present no dilatations, either at the 

 upper larynx, or in the course of the trachea, as are seen in them. This 

 fact is one of many tending to shew that the strictest affinity in some points 

 of structure is not always accompanied with a strict resemblance in some of 

 the organs supposed to exhibit generic peculiarities. The trachea of the 

 male of this species merely resembles that of the female of the other species. 

 Its rings are about 100; those of the bronchi 30. The contractor muscles 

 are strong, and terminate at the commencement of the lower larynx. There 

 are cleido-tracheal and sterno-tracheal muscles, but no inferior laryngeal. 



