2IO Experime^ital Zoology 



pariah dog in India. It would seem that the result must be due to 

 a single change of some sort in the germ that involves a correlated 

 change in many parts at once. 



The Mauchamp breed of sheep originated also from a single 

 individual ram that appeared in 1828. The wool is long and 

 straight, not frizzled as in the merino. The ram and his imme- 

 diate descendants showed also other new structural characters. 

 The individuals of this breed are ''of small size with large heads, 

 long necks, narrow chests, and long flanks." These pecuHarities 

 are removable by "judicious crosses and selection." 



A monstrous breed of cattle exists in South America, the 

 niata cattle, that must have originated from the introduced 

 cattle ; and to judge from its peculiarities, the breed must have 

 appeared as a sport, although its actual origin is unknown. 

 The upper Hp is drawn back and the nostrils are situated high 

 up. The exposed incisors give a pecuHar appearance to these 

 animals. The skull is much modified, the hind legs are shorter 

 than usual, etc. The animals breed perfectly true to their kind. 

 The short-horn cattle are also said to have originated from a 

 sudden variation. 



A most interesting case is that of the Japan peacock, or 

 black-shouldered kind. This form has appeared several times 

 in England and differs so much from the ordinary forms that 

 have given birth to it that it would be ranked as a different 

 species were not its parentage known. The birds breed true 

 and have been known to replace in time the flock from which 

 they arose. 



Several other cases are on record. Sports have been recorded 

 among domesticated fowls, pigeons, horses, mice (rhinoceros 

 mice), and frequently in plants of many kinds. They are known 

 to have furnished the basis for several domesticated races. Un- 

 fortunately exact information of the origin of races in this way 

 would only be recorded when the saltation had been large in 

 amount. When small, the change would be put down to fluctu- 

 ating variations, especially by breeders who have had heretofore 

 little interest in the difference between these two kinds of varia- 



