PREFACE vii 



plants, on the other hand, display great changes 

 within a few years. The perfection attained by 

 breeders and gardeners in the art of selection 

 enables them to produce entirely new forms in a 

 short time. For this purpose it is only necessary to 

 keep and propagate the animal or plant under 

 special conditions, when, after a few generations, 

 new species may be obtained, differing from the 

 original form in a much higher degree than do 

 many wild species, or even genera, from one 

 another. The importance of this fact cannot be 

 over-estimated in connection with the origin of 

 species." 



As regards illustrations, my acknowledgments 

 are due, and are hereby tendered, to the Trustees 

 of the British Museum, the Royal Spanish Society 

 of Natural History, the New York Zoological 

 Society, the Municipality of Lyons and Professor 

 C. Gaillard, the editor of The Field, Mr. R. J. 

 Cuninghame, Dr. R. E. Drake - Brockman, 

 Professor J. C. Ewart, Captain Stanley Flower, 

 Dr. Conrad Keller, Sir E. G. Loder, Bart., Mr. 

 Heatley Noble, Colonel H. Piatt, Mr. R. I. Pocock, 

 Colonel J. Manners-Smith, Mr. G. Stallard, and 

 Mr. Rowland Ward. 



Two photographs, sent by Colonel S. E. Prall, 

 Chief Medical Officer at Aden, arrived after the 

 text was in type. One represents two ewes of the 

 Bedouin or Arabian long-tailed breed (p. i86) from 



