106 
SCAUP DUCK. 
inches from the mouth, it swells out to four times its common 
diameter, continuing of that size for about an inch and a half. 
This swelling is capable of being shortened or extended ; it 
then continues of its first diameter for two inches or more, 
when it becomes flattish, and almost transparent for other two 
inches; it then swells into a bony labyrinth of more than two 
inches in length by one and a half in width, over the hollow 
sides of which is spread a yellowish skin like parchment. The 
left side of this, fronting the back of the bird, is a hard bone. 
The divarications come out very regularly from this at the 
lower end, and enter the lungs. 
The intention of Nature in this extraordinary structure is 
probably to enable the bird to take down a supply of air to 
support respiration while diving ; yet why should the female, 
who takes the same submarine excursions as the male, be en- 
tirely destitute of this apparatus ? 
SCAUP DUCK ANAS MARILLA Plate LXIX. Fig. 3. 
Le petit Morlllon ray4, Briss. vi. p. 416, 26. A Arct. Zool. No. 498. — Lath. 
Syn. iii. p. 500. — Peale's Museum, No. 2668. 
FULIGULA A.— Stephens.* 
Fullgula marilla, Stept. ConU Sh. Zool. xli. p. 108. — JBonap, Syn. p. 392. — 
North. Zool. ii. p. 457 Anas marilla, Linn. i. p. 19. — Scaup Duck, Mont. 
Ornith. Piet. i. and Supp. — Bew. ii. p. 339. — Canard milouinan, Temm. Man. 
ii. p. 865. — Nyroca mariUa, Flem. Br. Anim, p. 122. — Common Scaup Potch- 
ard, Selby, Illust. Br. Omit. pi. 66. 
This duck is better known among us by the name of the 
blue bill. It is an excellent diver, and, according to Willough- 
* Common also to both continents, and in Britain a most abundant sea duck. 
Though generally to be found in the poultry markets during winter, it is strong 
and ill flavoured, or what is called fishy, and of little estimation for the table. 
In the Northei’n Zoology, the American specimens are said to be smaller, but no 
other distinctions could be perceived ; a single northern specimen which I possess. 
