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2 1 . GREAT BLACK-HEADED GULL. Larus ichthyaelus,
Pall 48
22. COMMON GULL. Larus canus, Linn 49
23. HERRING-GULL. Larus argentatus, J. P. Gmelin. 51
21. LESSER BLACK-BACKED GULL. Larus fuscus, Linn. 55
25. GREAT BLACK-BACKED GULL. Larus marinus,Linn. 57
26. GLAUCOUS GULL. Larus glaucus, O. Fabricius . 59
27. Do. DO. Immature 00
28. ICELAND GULL. Larus leucupterus, Faber . . . 62
29. KITTIWAKE. Rissa tridactyla (Linn.) . . . . 63
30. IVORY GULL. Pagophila ebúrnea (Phipps) . . . 68
31. GREAT SKUA. Lestrls catarrhactes (Linn.) . . 69
32. TWIST-TAILED SKUA. Lestris poma for hinus,Texam.~\
33. Do. Do J
34. RICHARDSON'S SKUA. Les tris richardsoni, Swain son. 75
35. LONG-TAILED or BUFFON'S SKUA. Lestris parasiticus
(Linn.) 77
36. RAZORBILL. Alca torda, Linn 79
37. GREAT AUK. Alca impennis, Linn 81
38. COMMON GUILLEMOT. Uria troile (Linn.) . . . 83
39. BRÜNNICH'S GUILLEMOT. Uria bruennichi, E.
Sabine. Summer plumage 87
40. Do. Do. Winter plumage 88
41. BLACK GUILLEMOT. Uria grylle (Linn.) . . . 91
42. LITTLE AUK. Mergulus alle (Linn.) 94
43. PUFFIN. Fratercula árctica (Linn.) 96
44. GREAT NORTHERN DIVER. Colymbus glaciulis,\j'mu. 97
45. WHITE-BILLED GREAT NORTHERN DIVER. Colymbus
udumsi, G. It. Gray 102
46. BLACK-THROATED DIVER. Colymbus árcticas, Linn. 104
47. RED-THROATED DIVER. Colymbus septentrionalis,
Linn 105
48. GREAT CRESTED GREBE. Podiceps cristutus (Linn.). 109
49. RED-NECKED GREHE. Podiceps grkeigena (Bod-daert)
Ill