Xn TABLE OF CONTENTS. 



Page. 



Key to the Species and Subspecies of Laxus 581 



5. Larus hyperboreus Gunnerus 584 



6. Larus leucopterus Faber 590 



7. Larus kumlieni Brewster 593 



8. Larus nelsoni Henshaw 595 



9. Larus glaucescens Naumann 597 



10. Larus thayeri Broolcs 600 



11. Larus marinus Linnteus 601 



12. Larus schistisagus Stejneger 605 



13. Larus affinis Reinhardt 608 



14. Larus occidentalis Audubon 610 



15. Larus argentatus argentatus Pontoppidan 612 



16. Larus vegre (Palm^n) 618 



17. Larus californicus Lawrence 620 



18. Larus delawarensis Ord 623 



19. Larus canus Linna?us 627 



20. Larus brachyrhynchus Richardson 632 



Genus 4. Chroicocephalus Eyton 635 



Key to the Species of Chroicocephalus 636 



21. Chroicocephahis atricilla(Linnreusj 636 



22. Chroicocephahis fi-anklinii (Swainson and Richardson) 641 



23. Chroicocephahis Philadelphia (Ord. ) 645 



Genus 5. Hydrocoloeus Kaup 649 



24. Hydrocoloeus minutus (Pallas) 649 



Genus 6. Blasipus Bruch 652 



Key to the Species of Blasipus 652 



25. Blasipus heermanni (Cassin) 654 



26. Blasipus f uliginosus (Gould ) 656 



Genus 7. Creagrus Bonaparte 658 



■ 27. ('reagrus furcatus (Xeboux) 659 



Genus 8. Xema Leach ! 662 



28. Xema sabini (J. Sabine) 663 



Genus 9. Rhodostethia Macgillivray 668 



29. Rhodostethia rosea (Macgilli\Tay) 669 



Family Stercorariid^e. The Skuas and Jaegers 673 



Key to the Genera of Stercorariidre 674 



Genus 1. Megalestris Bonaparte 674 



Key to the Species of Megalestris 675 



1. Megalestris skua (Briinnich) 677 



Genus 2. Coprotheres Reichenbach 680 



2. Coprotheres pomarinus (Temminck) 681 



Genus 3. Stercorarius Brisson 686 



Key to the Species of Stercorarius 687 



3. Stercorarius parasiticus (Linnteus) 687 



4. Stercorarius longicaudus Vieillot 694 



Suborder Alc^. The Auk Tribe 700 



Family AtciDiE. The Auks : 701 



Key to the Genera of Alcidse*. 702 



Genus 1. Plautus Gunnerus 706 



1. Plautus alle (Linnaeus) 707 



Genus 2. Pinguiuus Bonnaterre 710 



2. Pinguinua impennis (Linnaeus) 711 



Genus 3. Alca Linnaeus 713 



3. Alca torda Linnaeus 714 



