352 



Collection of British Birds. 



9 & 10. Sterna nigra. Black Tern. 



11 & 12. — Yming. 



13 & 14. minuta. Lesser Tern. 



15. Young. 



l6. Thalassidroma Leachii. Leach's Petrel. 

 17 5j 18. pelagica. Stormy Petrel. 



Case XXI. 

 1. Larus marinus. Great Black-backed Gull. 

 Adult. 



Young. Second year. 



3. glaucus. Glaucous Gull. Young. First 



year. • 



i. 



5. fuscus. Lesser Black-backed Gull- 

 Adult. 



6. 



Young. Second year. 



7. — argentatus. Herring Gull. Adult. 



8. .... Young. 



Second year. 



9- 



Nestling. 



Case XXII. 



•1. Larus eburneus. Ivory Gull. 

 2. I tridactylus. Kittimake. Adult in Win- 



ter. 



3. Young. 



i. canus. Common Gull. Young. First 



Winter. 



5. . ridibundus. Laughing Gull. Second 



Summer; and Nestling. 



6. canus. Common Gull. Adult in Sum- 

 mer. 



7. ridibundus. Laughing Gull. Spring 



of second year. 



8. tridactylus. Kittimake. Adult in Sum- 

 mer. 



g. ridibundus. Laughing Gull. Winter 



plumage. 

 *]0. Lestris Catarractes. Skua Gull. 



*11. parasiticus. Arctic Gull. Adult Male. 



12. . Young Male. 



*13. Intermediate 



between Nos. 11 and 12. 



