558 P. W. WHITING 
c. The number of loci involved. The facts thus far collected, 
then, are consistent with the assumption of two loci, one for the 
banding factors and one for the ticking factors. Since, however, 
all variations from very light to very dark ticking occur and since 
dark-ticked cats heterozygous for black may produce kittens of 
somewhat lighter grade than themselves, it is probable that fac- 
tors at other loci recombine to modify the ticking. Tests are now 
being made which, it is believed, will determine definitely whether 
light ticking and dark ticking are both allelomorphic with the 
same factor for black; that is, whether they form a triple allelo- 
morphie series. 
The three types of banding, lined, striped, and blotched, are 
each entirely distinct. No intergrades have been observed. 
The natural assumption is to suppose that they form a triple 
allelomorphiec series, B’, B, and b, as I have tentatively assumed. 
But if two loci are involved the conditions might be expressed 
as follows: A lined cat might be LLBB, LLBb, LLbb, LIBB, 
LIBb, or Libb. A striped cat might be JBB or IlBb. A blotched 
cat would then be the double recessive, llbb. This scheme ap- 
parently fits the genetic data thus far collected. Striped and 
blotched would act as a pair of simple allelomorphs, B and b. 
The crosses involving the lined cats would be expressed by 
supposing that they are both of formula L/bb. Bred together 
they produced lined, LLbb or Libb, and blotched, llbb. Crossed 
with blotched, either black or ticked, llbb, they give lined, Llbb, 
and blotched, llbb. Crossed with homoyzgous striped, lIBB, 
they give lined, LIB}, and striped I1/Bb. 
The same crosses for testing the agouti factors will also test 
the allelomorphism of the banding factors. Other combinations 
that are being made with lined should give yellow and maltese 
lined. 
d. Physiology of color-production. Reference should now be 
made to Wright’s (17) papers on color inheritance in mammals. 
Wright classifies color factors according to their effects on either 
one of two enzymes. Enzyme 1 is the basic enzyme for color 
production which, acting alone on chromogem, produces yellow. 
Enzyme 2 is supplementary to enzyme 1. It has no effect alone 
