COAT CHARACTERS IN GUINEA-PIGS AND RABBITS. 7 



the animal, are black throughout their length, lacking entirely the 

 subapical yellow band. On the lower side of the body the hairs have 

 a pigmentation similar to that of the ticked hairs of the back, but the 

 yellow band is longer and less sharply limited, and the black tip is 

 inconspicuous, so that the fur appears superficially of a dull yellow 

 color, but when parted is seen to be leaden black at the base. 



COLOR VARIETIES OF DOMESTICATED CAVY OR GUINEA-PIG. 

 In the various color varieties of domesticated cavies the same three 

 sorts of pigment found in the wild animal exist singly or in combina- 

 tions sometimes identical with those found in the wild animal, some- 

 times different. 



AGOUTI. 



In the agouti variety, of which there are two distinct sub-varieties, 

 known respectively as golden and silver agouti, all three pigments are 

 present, distributed as in the wild cavy. In the golden agouti the 

 pigments of all three sorts are abundant and dark, so that the yellow 

 band becomes a red of the sort found in a sorrel horse, while the 

 remaining portions of the hair are fairly deep black. In silver agouti 

 the pigmentation is less heavy. It may fairly be described as a dilute 

 condition of the golden agouti. The yellow band is of a pale yellow 

 color, and the black portions of the hair are a pale or bluish black. 

 Silver agouti may be produced by crossing golden agoutis with albino 

 animals of a particular sort, as will be explained presently. 



YELLOW. 



Yellow-coated varieties, with hair containing neither black nor* 

 chocolate pigment, are distinguished according to the depth of their 

 color, as red, yellow, or cream. 



In the lighter shades, as compared with the darker ones, the pigment 

 granules are smaller and possibly less numerous. The skin covering 

 the feet and ears of animals of this variety contains chocolate pigment, 

 and, at least in some cases, black also ; the eye, too, certainly contains 

 chocolate pigment as well as black, yet the hair, as stated, never con- 

 tains black or chocolate pigment. 



CHOCOLATE. 



Of the chocolate variety I have made as yet a very incomplete study, 

 for lack of material. The two animals which I. have had bore one a 

 spot of red, the other a spot of yellow. Neither bore any black hairs. 

 The chocolate hairs apparently contain no other pigment. Theoretically 

 it should be possible to obtain a chocolate-colored animal entirely free 

 from yellow as well as from black pigment, as is possible with mice 

 (see Allen, : 04). My experiments have not progressed far enough to 

 show whether this expectation can be realized. 



