184 HYBRIDIZING AND INCUBATION. [CHAP. v. 



domestic race, a small albino variety is frequently 

 bred in cages, in different parts of India, with wings 

 measuring 5^ to 6 inches; but its form of tail and 

 other proportions are as in T. -risorius and T. vinaceus. 

 This bird is often interbred with the cream-coloured 

 race, producing offspring of intermediate size and shade 

 of colouring." I have seen birds of this kind, under 

 the name of White Persian Doves, and believe them to 

 be specifically distinct, and of considerable ornithological 

 interest. The black collar is entirely obliterated : in 

 the White Turkey, it should be remembered, the breast- 

 tuft remains black. The circumstance of interbreeding 

 is not, just now, of much force either way. 



At the Regent's Park Zoological Gardens, in 1848, 

 were two strange hybrids between the Passenger Pigeon 

 of North America and the Collared Turtle of North 

 Africa. In outline and proportion they most resembled 

 the former parent, in size they not much exceeded the 

 latter progenitor. They certainly were handsome crea- 

 tures, without any look of being artificial or unnatural. 

 But they were both males : and the object then was to 

 obtain a female or two from the same cross, and so found 

 a new species, Quod erit demonstrandum. It is odd 

 that, in such interminglings of what the Creator sent 

 forth pure and sincere, the result, if any, should almost 

 always be males ; the female chicks, we may suppose, 

 having too feeble a hold on life to come into actual 

 existence or prolonged vitality, and the males being 

 mostly useless for further increase of their kind. 



A wide distinction between the Pigeons and the 

 Turtles is indicated by the time of incubation of our 

 present bird being only fifteen days from the laying of 



