314 MISCELLANEOUS OBJECTIONS TO THE [Chap. VII 



would extend the same view to the wings of bats and 

 pterodactyles. This conclusion, which implies great 

 breaks or discontinuity in the series, appears to me im- 

 probable in -the highest degree. 



Every one who believes in slow and gradual evolu- 

 tion, will of course admit that specific changes may have 

 been as abrupt and as great as any single variation which 

 we meet with under nature, or even under domestication. 

 But as species are more variable when domesticated or 

 cultivated than under their natural conditions, it is not 

 probable that such great and abrupt variations have 

 often occurred under nature, as are known occasionally 

 to arise under domestication. Of these latter variations 

 several maybe attributed to reversion; and the characters 

 which thus reappear were, it is probable, in many cases 

 at first gained in a gradual manner. A still greater 

 number must be called monstrosities, such as six-fingered 

 men, porcupine men, Ancon sheep, Niata cattle, &c.; and 

 as they are widely different in character from natural 

 species, they throw very little light on our subject. Ex- 

 cluding such cases of abrupt variations, the few which re- 

 main would at best constitute, if found in a state of na- 

 ture, doubtful species, closely related to their parental 

 types. 



My reasons for doubting whether natural species 

 have changed as abruptly as have occasionally domestic 

 races, and for entirely disbelieving that they have 

 changed in the wonderful manner indicated by Mr. Mi- 

 vart,are as follows. According to our experience, abrupt 

 and strongly marked variations occur in our domesti- 

 cated productions, singly and at rather long intervals of 

 time. If such occurred under nature, they would be 

 liable, as formerly explained, to be lost by accidental 



