VARIATION UNDER DOMESTICATION 19 



There can be no doubt that a race may be modified by 

 occasional crosses, if aided by the careful selection of 

 those individual mongrels, which present any desired 

 character ; but that a race could be obtained nearly 

 intermediate between two extremely different races or 

 species, I can hardly believe. Sir J. Sebright ex- 

 pressly experimentised for this object, and failed. The 

 offspring from the first cross between two pure breeds 

 is tolerably and sometimes (as I have found with 

 pigeons) extremely uniform, and everything seems 

 simple enough ; but when these mongrels are crossed 

 one with another for several generations, hardly two 

 of them will be alike, and then the extreme difficulty, 

 or rather utter hopelessness, of the task becomes 

 apparent. Certainly, a breed intermediate between 

 two very distinct breeds could not be got without 

 extreme care and long-continued selection ; nor can I 

 find a single case on record of a permanent race having 

 been thus formed. 



On the Breeds of the Domestic Pigeon. — Believing 

 that it is always best to study some special group, J 

 have, after deliberation, taken up domestic pigeons. 

 I have kept every breed which I could purchase or 

 obtain, and have been most kindly favoured with skins 

 from several quarters of the world, more especially by 

 the Hon. W. Elliot from India, and by the Hon. C. 

 Murray from Persia. Many treatises in different 

 languages have been published on pigeons, and some 

 of them are very important, as being of considerable 

 antiquity. I have associated with several eminent 

 fanciers, and have been permitted to join two of the 

 London Pigeon Clubs. The diversity of the breeds is 

 something astonishing. Compare the English carrier 

 and the short-faced tumbler, and see the wonderful 

 difference in their beaks, entailing corresponding 

 differences in their skulls. The carrier, more especially 

 the male bird, is also remarkable from the wonderful 

 development of the carunculated skin about the head, 

 and this is accompanied by greatly elongated eyelids, 

 very large external orifices to the nostrils, and a wide 



