Based on the data collected for 10 years (1951-1960) from the following three different crosses of the fox, silver × silver, platinum × platinum and silver × platinum, the litter-size, sex-ratio and the segregation of coat color in kits were observed. The results are summarized in Tables 1 to 4 and Figure 1.
Platinum character is dominant over the silver. The individuals homozygous for platinum gene are lethal. The crosses of platinum × platinum produce silver and platinum individuals at 1:2. The litter-size differs by the type of cross. In the cross of silver × platinum, the litter-size is very small and approximates that of the cross, platinum × platinum. This seems to be due to the fact that the foetuses from the silver × platinum cross die before parturition.
The sex-ratio is regular in every cross examined in this study; this shows that both silver and platinum are autosomal characters.
