Heredity and Natural Selection. 301 



realized a large price; it is therefore improbable that it 

 shouKi have been silently introduced, and its history 

 subsequeuily lost. On the whole the evidence seems to 

 me, as ic did to Sir II. Heron, to preponderate strongly 

 in favor of the black-shouldered breed being a variation, 

 induced either by the climate of England or by some 

 unknown cause, such as reversion to a premordial and 

 extinct condition of the species. On the view that the 

 black -shouldered peacock is a variety, the case is the 

 most remarkable ever recorded of the abrupt appearance 

 of a new form which so closely resembles a true species 

 that it has deceived one of the most ex23erienced of liv- 

 ing ornithologists." 



Mivart quotes from Naudin, Godron, and others, sev- 

 eral very similar cases in plants. From the seeds of a 

 poppy, which suddenly took on a remarkable variation 

 in its fruit, a crown of secondary capsules being added 

 to the normal central capsule, a field of poppies was 

 grown. These resembled the form from which the seed 

 was taken, and gave seed which again reproduced the 

 variation. In 1861 Godron *^ observed among a sowing 

 of Datura fatula, the fruits of which are very spinous, 

 a single individual of which the capsule was perfectly 

 smooth. The seeds taken from this plant all furnished 

 plants having the character of this individual." These 

 seeds were cultivated up to the fifth and sixth genera- 

 tions, and the latest descendants did not exhibit the 

 least tendency to revert to the spinous form. 



These cases show us that very considerable variations 

 may suddenly appear in cultivated plants and domesti- 

 cated animals, and that these sudden modifications may 

 be strongly inherited, and may thus give rise to new 

 races by sudden jumps. 



The analogy of domesticated forms would lead us to 



