AMERICAN SCOTER DUCK. 
57 
other species in having the sides of the unguis narrowed, and the orango 
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 lamellae 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 9i 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-J 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 h 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, lh twelfths long, form a belt 1^ 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 8 inches in length, 2£ twelfths in their 
greatest diameter,' with the extremity obtuse. 
The trachea is 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 perspicittata and F. fusca. 
The bronchi, however, are of very large size, being 1 inch 4 twelfths long, 
their greatest breadth h 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. 
Vol. VII.— 8 
