ALLEN. — THE HEREDITY OF COAT COLOR IN MICE. 153 



golden-agouti and cliocolate young. It is therefore expected tliat these 

 albinos, on being back-crossed with mice of their parents' type, will 

 give either chocolate or golden-agouti young, but not gray or black 

 offspring. This experiment is still in i)rogress. _^ 



5. Comparison icith Mirahilis. The behavior of pigments in the case 

 of mice seems to be somewhat similar to that recorded by Correns 

 (:02) in certain varieties of Mirabilis. Several types of blossoms are 

 recognized which, as regards pigment characters, may probably be 

 reduced to three, viz.: (1) red, with which is to be included the rose- 

 type, a " dilute " form of red; (2) yellow, which occurs also in a dilute or 

 i/ellowish form ; and (3) the albino. These several types breed true as 

 a rule. Red corresponds to gray in mice, and is probably a combina- 

 tion of red with yellow chloroplasts. Pied varieties occur, as with 

 mice. Correns found that red X albino gave all red blossoms, which 

 shows either that red is a simple dominant over whatever pigment- 

 character the albino may have contributed, or that the latter also con- 

 tained the red character. The ancestry of the albinos is not given. A 

 cross of albino with rose resulted, however, in rose flowers, so that the 

 former may have transmitted red in the dilute form. At illl events, no 

 yellow flowers were produced. A third cross was made between the 

 yellowish stock and the albino. The latter doubtless had the red pig- 

 ment-character present in dilute form, and was dominant over yellow, for 

 rose flowers were produced. This result is like that obtained by pairing 

 albino mice of gray ancestry with other types lacking one or two of the 

 three color elements, so that the gray results either through dominance 

 or through combination of all the color characters. When the albino 

 type of Mirabilis was crossed with the bright (i. e., undiluted) yellow 

 type, full red flowers resulted. The albino used in each of these crosses 

 with the yellow sort must have transmitted the red character in dilute 

 form, for with the dilute yellow type dilute red or rose flowers resulted, 

 while with the/«W red type full red flowers were produced. The former 

 cross is therefore quite the same as that in which dilute red and dilute 

 yellow are crossed, giving blossoms of the former or rose type. It is 

 therefore fairly clear that the albino forms of these plants may trans- 

 mit pigment-characters just as do the albino mice. The data given 

 by Correns as to the behavior of the spotted character do not show very 

 conclusively whether or not it is recessive toward the character total 

 pigmentation. One cross of the albino with mottled white-and-red gave 

 some of the spotted type and a less number that were all red. 



