250 



The Journal of Heredity 



occurrence. We once received a self- 

 black, but the first rainstorm proved 

 that the so-called "sport" was not fast 

 black, either somatically or genetically. 

 It was promptly returned. There- 

 fore in listing these mutations we have 

 carefully eliminated all questionable 

 cases. 



Breeding investigations were begun 

 in 1914 with such mutants as could be 

 purchased, and on as large a scale as 

 funds and space would allow. The 

 earlier matings were made by the 

 Skunk De\'elopment Bureau, near Chi- 

 cago, but in 1916, it became necessary 

 to move the stock on hand to the 

 Illinois Agricultural Experiment Sta- 

 tion. This move hampered our experi- 

 ments because the animals needed 

 much more room and less disturbance 

 for their proper care. They were 

 housed in dens in a small yard about 10 

 feet wide and 30 feet long. The dens 

 and cages were of the type described by 

 Holbrook in 1915.« 



The first mutant, a, typical albino 

 female with pink eyes, failed to breed 

 and died soon after her arrival, due to 

 her poor condition. 



Mutant female, h (white fur with 

 brownish hair on her face and extremi- 

 ties, and black eyes), was successfully 

 mated to a high grade wild star black 

 male on March 4, 1915 and produced 

 three black young of rather high 

 grade striping on or about May 11. 

 The period of gestation is thus about 

 65 days or less. The young (see Fig. 6) 

 were : 



9 1. ] these were wild black, with 

 very short white stripes. cfl 

 and 92 bred together gave an 

 F2 generation. 



2. 

 2a. 



died before maturity. 

 Fortunately 9l and c^2 were success- 

 fully bred during the next spring in 

 1916 and gave a litter of seven F2 

 young as follows: 

 914] 



Q 15 1 These young were wild black 

 .-[with variable amounts of white 

 ,18 [striping. 



9l9j 



20 [white, with black eyes like grand- 

 f dam, 9 mutant b. 

 The dam (9I) killed her young but 

 sufificient data were secured to demon- 

 strate that mutant b was a real discon- 

 tinuous and genetic variation, rather 

 than a wide fluctuation. The amount 

 of white in the striped pattern of skunks 

 varies so much that a black-eyed 

 white might seem to represent an 

 extreme in the spotting series, similar 

 to the black-eyed white guinea-pig. 

 There can be no doubt as to the simple 

 Mendelian nature of this germinal 

 change. The white Fo ( 9 20) had 

 pigmented eyes exactly like her grand- 

 dam, mutant 9 b. The rest of the 

 litter was normal black with variable 

 amounts of striping. No further inves- 

 tigation was possible with this muta- 

 tion, for the original mutant h was old 

 when captured and produced no more 

 young, and the Fi generation failed to 

 breed again. This type of mutation 

 is evidently a Mendelian recessiA'e, and 

 a pure race should not be difficult to 

 obtain. It would not be as valuable 

 however as a race from mutants c or g 

 which were pure white. 



Mutant c, an albino female with a 

 very fine pencil line of pigment around 

 the inner and outer margins of the iris, 

 was mated successfully in 1915 and 

 again in 1917. The first mating was 

 made to a very high grade star-black 

 male on March 4, 1915 (male removed 

 April 18) and seven extremely high 

 grade young were born on or about 

 May 9, 1915. Such a uniformly high 

 grade litter (see Fig. 7) from a high 

 grade male by a female of unknown 

 pattern factors, probably indicates the 

 germinal nature of the variations in 

 pattern and gives some assurance of 

 producing a high grade race through 

 selection. One female (see Fig. 3) was 

 remarkable in that she showed as an 

 adult only two small patches of white 

 over the ears, (each patch co\'ering 

 less than two square centimeters), and 

 very few white hairs at the tip of the 

 tail. Our records point again to a ges- 

 tation period of 65 days or less. We 

 are not certain that the young were not 

 born a few days before May 9, for 



ment 



Holbrook, F. M., 1915. Skunk Culture for Profit, pp. 1-142, ill. Publ. by Skunk Dcvdop- 

 : Bureau, White Plains, N. Y. 



