RED-BREASTED MERGANSER. 5 
elegantly crossed with numerous waving lines of black ; belly 
and vent, white ; legs and feet, red; the tail, dusky ash ; the 
black of the back passes up the hind neck in a narrow band 
to the head. 
The female is twenty-one inches in length, and thirty in ex- 
tent ; the crested head and part of the neck are of a dull sorrel 
colour ; irides, yellow; legs and bill red, upper parts, dusky 
slate ; wings, black ; greater coverts, largely tipt with white ; 
secondaries nearly all white; sides of the breast, slightly 
dusky ; whole lower parts, pure white; the tail is of a lighter 
slate than the back. The crest is much shorter than in the 
male, and sometimes there is a slight tinge of ferruginous on 
the breast. 
The windpipe of the male of this species is very curious, 
and differs something from that of the goosander. About two 
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 ? 
