The Making of Species 



over-rate small differences when drawing up a 

 classification. It would be therefore safe to say, 

 in the present state of our knowledge, that species 

 belonging to different natural families cannot 

 hybridize. 



In some cases multiple hybrids have been 

 produced. Thus, at the London Zoological 

 Gardens, many years ago, a hybrid between the 

 Gayal of India (Bos frontalis] and the Indian 

 humped cow mentioned above was put to an 

 American bison, and produced a double hybrid 

 calf. 



M. G. Rogeron of Angers bred many hybrids 

 from a male pochard and a duck bred from a 

 Mallard and a Gadwall. 



More recently, Mr J. L. Bonhote has suc- 

 ceeded in combining the blood of five wild species 

 of ducks in one individual. 



Mr J. T. Newman has also bred turtle-doves 

 containing the blood of three distinct species. 



A cross, which usually results in sterile 

 offspring, may in very rare cases produce a fertile 

 individual ; thus, Mr A. Suchetet once succeeded 

 in obtaining a three-quarter-bred bird from the 

 not uncommon hybrid of the tame pigeon and 

 tame collared dove (Turtur risorius\ which is 

 usually barren, by pairing it with a dove ; but the 

 bird thus produced, when again paired with a 

 dove, was itself sterile. 



Some of the cases here given seem to encourage 

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