RESULTS OF HYBRIDIZING RING-DOVES. 295 



hybrids between the dark or blond ring-dove and the white ring- 

 dove suggesting Mendelian phenomena (see Fig. i). These 

 birds breed true to type when not crossed, and they have a very 

 simple color pattern. They do well in cages. Variations are 

 so small that a very careful examination under very favorable 

 conditions is required to distinguish individuals. 



According to Salvadori ('93), the tame ring-doves are of 

 unknown ancestry, but the dark form is referred to the species 

 Turtur risorius, sub-genus Streplopelia. In Sharpe's Handlist 

 (Sharpe, '99, p. 78) the term Streptopelia risoria Linn, is em- 

 ployed. 



Salvadori ('93, p. 415) considered the white ring-dove, Turtur 

 alba, to be a white variety of Turtur risorius, though he mentions 

 the fact that Temminck and others have regarded the white 

 bird as a distinct species. Whether the white and the blond 

 ring-doves are to be regarded as different species must of course 

 depend on the criterion employed. If the inter-breeding test 

 which is involved in the code of the American Ornithologists' 

 Union is applied, they cannot be called distinct species as they 

 cross freely when together. However, Professor Whitman and 

 others have produced many hybrids between species of doves 

 often very distantly related. Only the freedom with which 

 mating occurs and the apparently perfect fertility of the hybrids 

 can be cited as distinguishing these ring-dove crosses from 

 those between distinct species. The white ring-dove differs 

 from the blond form chiefly in lacking the pigmentation of the 

 latter. The blond bird has a dark bill which is about the color 

 designated by No. 25 in the "Code des Couleurs" of Klincksieck 

 et Valette ('08). The beak of the white bird has a very light 

 flesh-colored tint and is about 071 in the system just mentioned. 

 Both have red feet about 17 in color. The skin of the blond 

 bird is darker than that of the white bird. 



Except for the black neck-ring, the predominating colors of 

 the blond dove are fairly well indicated as lying between No. 103 A 

 and 1030 (see Sharpe, '93, for a detailed description). For 

 practical purposes in this paper, it is sufficient to describe the 

 color of the blond ring-dove plumage as due to a dilute melanin 

 pigmentation. Relatively small numbers of chromatophores 



