6 INHERITANCE IN GUINEA-PIGS. 



it may be said that the rough-coated long-haired variety has ever since 

 its introduction been called by fanciers " Peruvian." I saw no long- 

 haired individuals, either rough-coated or smooth, among the guinea- 

 pigs kept by the natives at Arequipa, and the short-haired rough-coated 

 ones observed had imperfectly developed rosettes, much inferior to 

 the best standard-bred resetted Abyssinians of fanciers in Europe and 

 the United States. For this reason I infer that no particular attention 

 was given to this character in the breeding of the guinea-pigs which I 

 saw, though this may very likely have been done in other parts of the 

 country. But the unit-character variation which is responsible for the 

 resetted condition of the coat in Abyssinian guinea-pigs was plainly 

 represented in the stocks kept by the natives in Arequipa and needed 

 only selection to bring it up to the standards of fanciers. 



Eight independent mendelizing unit-character variations had been 

 recognized as affecting the coat characters of guinea-pigs up to this 

 time. Six of these were represented among the four or five dozen 

 guinea-pigs which I actually saw in the cabins of natives, the other 

 two unit characters being (1) the long-haired variation which, as 

 already noted, is said to have been brought originally from Peru to 

 Europe; and (2) the brown variation which first came to the notice 

 of fanciers in England about 1900 and was certainly in existence before 

 that time in the United States, as I can state from personal knowledge. 

 It is uncertain whether or not this last variation had already occurred 

 in Peru and was thence transferred to Europe, but it is certain that all 

 the other 7 had done so, and it is very probable that this also originated 

 in Peru. Further, a ninth wholly independent unit-character variation 

 (presently to be described, viz, the pink-eyed variation) has made its 

 appearance in stocks of domesticated guinea-pigs obtained by me at 

 Arequipa in 1911 and by my colleague, Professor C. T. Brues, at Luna, 

 in 1912. So it is clear that this variation also is widely disseminated 

 among domesticated guinea-pigs kept by the natives in Peru and which 

 have never been in the hands of European fanciers at all. 



It can be stated, therefore, with probable correctness, that the guinea- 

 pig has undergone in domestication more extensive variation in color 

 and coat characters than any other mammal, and that this variation 

 has occurred almost if not quite exclusively under the tutelage of the 

 natives of Peru. This conclusion points either to a great antiquity 

 of the guinea-pig as a domesticated animal or to more rapid evolution by 

 unit character variation than by other natural processes. 



That the natives do give careful attention to the selection of animals 

 for breeding is shown by the following incident : In the cabin near the 

 observatory, where I first saw guinea-pigs in Peru, and where I ulti- 

 mately secured two pairs of animals, one of which I brought back with 

 me, I observed a very large individual which I desired to purchase, 

 and though other individuals were offered me at a very reasonable price, 



