ALLEN. — THE IIRRKniTY OF COAT COLOR IN MICE. 03 



tored among these particolored hairs are others, less numerous hut longer 

 and entirely black, so that the combined effect is the " house mouse gray." 

 The centre of the dorsal surface is slightly darker than the sides, while 

 the ventral surfaces are covered (though more thinly) with hairs plum- 

 boons at the base, but with the tips varying in different individuals from a 

 dirty white to a very pale ochraceous tint. The ears, tail, and feet are 

 spaisely covered with short, light gray hairs, and the skin of these parts is 

 dark gray. The ochraceous bands on the particolored hairs of the uppcjr 

 surfaces deepen in tint with the age of the individual, so that old adults 

 often have a rufous tinge on the flanks. 



From gray house mice such as these it is supposed that the various 

 domesticated breeds have arisen. Bateson (rOS**) has published the 

 partial results of an examination by Miss F. M. Durham of the pigments 

 contained in the hair of house mice. These are found to be three: (1) 

 densely opaque black, (2) less opaque brown, and (3) transparent yellow. 

 All three pigments may coexist in the same hair, or certain hairs may 

 contain only black and brown, others only black and yellow. The pres- 

 ent writer also has found these three pigments in one or another of the 

 strains of mice with which he has experimented. According as one, two, 

 or all three of these pigments are present in greater or less degree, the 

 mouse is referred by fanciers to a particular color type. Bateson has 

 given a list of the types known to him, enumerating in all thirteen. 

 These, in brief, are as follows : 



(1) Ordinary cinnamon, or agouti, bein^- the usual "wild gray," in 

 which all three pigments are present in the hairs. 



(2) Golden agouti, a distinctly tawny type, containing the yellow and 

 brown pigments in the hairs, but not the black. 



(3) Sable, of the agouti type, but with the Hanks nearly clear yellow. 



(4) Blue-and-tan, believed by Bateson to be the same as "sable " but 

 with less of the black pigment. 



(o) Chocolate or plum, containing the brown pigment alone. 

 (G) Silver fawn, a very light chocolate. 



(7) Yellow, containing yellow only. 



(8) Cream, a very light, or " diluted " yellow. 



(9) Black, containing, according to Bateson, black and brown, the 

 former not extending to the tips of the large contour hairs. The same 

 author states that he has not seen a pure black, i. e., one without the 

 brown pigment. 



(10) Blue, a "dilute" form of black, the pigment granules being less 

 numerous. 



