ScoTER. NATATORES. OIDEMIA. 329 
ing, for which their formation is well adapted ; and they are 
able to remain for a long time submerged. They rarely 
quit the water, except for incubation; and their flight, though 
usually near the surface, is yet strong and rapid. Upon re- 
viewing the species hitherto assigned to this genus, I am in- 
clined to think that Oidemia nigra, Oid. leucocephala, and 
another (said to be new) from North America, will have to 
be separated from Oid. fusca, Oid. perspicillata, not only on 
account of the difference of form shewn in the basal part of 
the bill, but also from the relative proportions of the wings. 
In Oid. nigra, the first quill is shorter than the second, and 
its anterior part very narrow in consequence of a deep notch 
or emargination at about half its length. In Oid. fusca and 
perspicillata, on the contrary, the first quill is the longest, 
and without any emargination whatever. The gradation 
from the Velvet Scoter (Oid. fusca), through Oid. perspi- 
cillata, to the Eiders is gradual, and presents a beautiful in- 
stance of the affinities that connect the various genera with 
each other. 
BLACK SCOTER. 
Omemi4 NiGRA, Flem. 
PLATE LXVIII. 
Oidemia nigra, Flem. Br. Anim. 1. 119. sp. 174.—Shaw’s Zool. 12. 213. 
pl. 59. 
Anas nigra, Linn. Syst. 1. 196. 7.—Gmel. Syst. 1. 508.—Zath. Ind. Orn. 
2. 848. sp. 43.—Briss. 6. 420. 28. t. 38. f. 2. Wils. Amer. Orn. 8. 135. 
pl. 92. f. 2. 
Anas nigra minor, Raii Syn. 141. A. 5.—Will. 280. t. 94. 
La Macreuse, Buff: Ois. 9. 234. t. 16.—Id. Pl. Enl. 978. 
Canard Macreuse, Temm. Man. d’Orn. 2. 856. 
Die Trauer Ente, Bechst. Naturg. Deut. 4. 963. 
Scoter or Black Diver, Penn. Br. Zool. 2. 584. No. 273.—Arct. Zool. 2. 
484.—Lath. Syn. 6. 480.—Lewin’s Br. Birds, 7. pl. 249.—Mont. Orn. 
Dict. and Sup.—Bewick’s Br. Birds, 2. ed. 1826, p. t. 322.—Wils. 
Amer. Orn. 8. 135. pl. 92. f. 2. 
Black Scoter, Flem. Br. Anim. 1. 119. sp. 174.—Shaw’s Zool. 12. 213, pl. 
59. 
Anas cinerascens, Bechst. Naturg. Deut. 4. 1025. 
Canard Grisette, Temm. Man. @Ornith. 1. ed. p. 555. t Young: 
