Now for conjectures. These enormous dilatations are intended for strengthening the voice. But the voice is not strong in this duck. Well, then, they are receptacles of air, to enable the bird to keep longer under water. But the bird does not keep longer under water than many other ducks, and besides, the female, which has no such dilatations, dives as well as the male. One use at least is this. A comparison of the windpipe of an American Golden-eye, with those of two Scotch ones, shews that the so-called _Clangula Americana_, is in this respect precisely similar to the _Clangula chrysophthalma_. Their digestive organs are also the same; and American skins compared with European skins, exhibit no differences of the slightest importance. Some individuals, especially males, have much larger bills than others, but this happens in the birds of both countries, and the Golden-eye is not singular in this respect. _Clangula Americana_, therefore, requires a better elucidation than the appendage of a “Nob,” before it can be admitted as a species. RUDDY DUCK. _FULIGULA RUBIDA_, BONAP. PLATE CCCXLIII. MALE, FEMALE, AND YOUNG. Look at this plate, Reader, and tell me whether you ever saw a greater difference between young and old, or between male and female, than is apparent here. You see a fine old male in the livery of the breeding season, put on as it were expressly for the purpose of pleasing the female for a while. The female has never been figured before; nor, I believe, has any representation been given of the young in the autumnal plumage. Besides these, you have here the young male at the approach of spring. The Ruddy Duck is by no means a rare species in the United States; indeed I consider it quite abundant, especially during the winter months, in the Peninsula of Florida, where I have shot upwards of forty in one morning. In our Eastern Districts they make their appearance early in September, and are then plentiful from Eastport to Boston, in the markets of which, as well as of New York, I have seen them. On the Ohio and Mississippi they arrive about the same period; and I have no doubt that they will be found breeding in all our Western Territories, as soon as attention is paid to such matters as the searching for nests with the view of promoting science, or of domesticating birds which might prove advantageous to the husbandman.