E. the factor for extension of pigment which when present turns a yellow into an agouti, or a tortoise into a black.

S. the factor for self colour which turns a Himalayan into a self coloured animal.

All the rabbits in this experiment contain the factor for black (B).

M 2.

The Himalayan pattern can occur in all four colour classes. Thus the agouti Himalayan has lighter points than the black Himalayan. (cf. 2 specimens shown.)

Experiments to demonstrate that black rabbits may be of different constitution genetically.

Factors concerned in these experiments are:—

A. the agouti factor.

E. the factor for extension of pigment.

D. a factor for density of pigmentation.