116 Clark, Tail-feathers and Coverts. [£££ 



of this paper, I ignore them. This statement of my observations 

 is purely introductory and is not intended to be as dogmatic as it 

 sometimes appears. 



.1. Coverts and rectrices of the same number. 



4-4. Crotophaga. 



5-5. Trochili. Cyseli. Caprimulgi. Cuckoos. Toucan 



(Selenidera). Jacana. Botaurus. 

 6-6. Pici. Columbse. Most Accipitres. Curassows. Nearly 



all waders and shore-birds. Cranes. Most terns and 



small gulls. Cormorants. Gannets. Man-of-war-birds. 



Petrels. 

 7-7. Zenaidura. Gannets. 

 8-8. A single individual of Lagopus. 

 9-9. Tctrao. 

 10-10. Pelicans. Loons. Penguin. 



II. Coverts more numerous than rectrices. 



Except in some owls and the remarkable case of the toucan given 

 below, the additional coverts are at the base of, or beyond, the 

 outermost rectrix on the side of the pygidium. In owls having 6-7, 

 the extra covert seems to be between 4 and 5 but probably this is 

 due only to shifted positions of 5, 6 and 7. 



5-6. A single individual of Botaurus, on one side only. 



6-7. Owls. Osprey. Cancroma. A single individual Fla- 

 mingo. Some gulls. 



6-8. Some young owls. Some ospreys. Anhinga. Albatross. 

 Cepphus. 



6-9. Some individuals of Cepphus and some albatrosses. 



7-8. Flamingo. Most ducks. 



7-9. Some ducks. 



8-9. Some ducks. Geese. Fratercula. 



8-10. Dafila. Ossifraga. 



9-10. Some ducks. 

 10-12. Swan. 



