61 



Ca.se 229 — continued. 



with the exception of the white patch on the wings, which is here 

 mottled, resembles the winter plumage of the adult, so that with this 

 exception the changes here shown are undergone each year in both 

 sexes. 



HERRING GULL {Larus argentatus). 



The front six specimens of this species illustrate the yearly change 

 of plumage from the chick to the adult in five years. The two specimens 

 at the back are intermediate stages of the third year. 



KITTIWAKE GULL {Rissa tridactyla). 

 Contrast of immature and adult plumage. 



GREAT BLACK-BACKED GULL {Larus marinus). 

 A specimen in immature plumage. The adult may be seen in the 

 group of the Great Black-backed Gull, Case 208. 



EIDER DUCK {Somateria moUissima) (male). 

 Six specimens showing the gradual change in the moulting from the 

 dark brown to the full adult male plumage. 



Case 230. 



Domesticated Birds. 



A case of specimens illustrating recognized varieties of birds in 

 domestication, which have been derived by artificial selection from 

 ancestors in a state of nature. 



THE COMMON CANARY {Serinus canaria). 



About twenty recognized varieties of the Common Canary have 

 been produced from it by artificial selection and pedigree breeding. 

 Of these many are shown by prize or exhibition specimens, so that the 

 points of each fancy are well displayed. 



There are also several specimens of hybrids produced by crossing 

 with Finches, and by other crosses. 



THE ROCK PIGEON [Columha livia). 

 There are upwards of 200 varieties of Domestic Pigeon, all produced 

 by artificial selection from a common ancestor, the Rock Pigeon. 

 A few of the more well-marked varieties are here on exhibition, sufficient 

 to show the extreme types of variation brought about. Many of these 

 specimens are prize birds, most typical of the fancy they represent. 



