2$8 EVOLUTION OF TO-DAY. 



were produced resembling true hybrids ; and in the 

 second generation they reverted to the original type, 

 just as is the case in true hybrids between species. 

 A more remarkable case still, is the appearance in 

 five distinct cases in England, of a special new breed 

 of peacock known as the black-shouldered variety, 

 which was so different from the ordinary form that 

 Dr. Sclater regarded it as a distinct species This 

 animal was produced in flocks of peacocks composed 

 entirely of the ordinary kind, making its appearance 

 suddenly by ordinary generation. This variety was 

 allowed to remain with the others and breed freely 

 with them, but even under these conditions, in some 

 cases, it increased in numbers until it replaced the 

 previously existing form. These three instances 

 will serve as illustrations of extraordinary births. 

 Many others might be given, most of which have 

 been collected by Darwin, who is the greatest 

 authority on variations of all kinds. Naturally all 

 of these instances occur in domestic animals or in 

 plants, for it would be impossible to distinguish 

 them among wild animals. If such an individual 

 were found in nature there would be no means of 

 knowing how it arose. It would, of course, be set 

 down as a new variety or species and that would be 

 all that would be known about it. Probably many 

 such individuals have been found and are in our 

 collections now ; but since there is no means of 

 telling how they arose they are called examples of 

 rare species. 



These extraordinary births do then occur, and 

 Mr. Mivart thinks they represent the beginning of a 



