[From the several foregoing facts we see that reversion in the feral state
gives no indication of the colour or size of the aboriginal parent-species.
One fact, however, with respect to the colouring of domestic dogs, I at one
time hoped might have thrown some light on their origin; and it is worth
giving, as showing how colouring follows laws, even in so anciently and
thoroughly domesticated an animal as the dog. Black dogs with tan-coloured
feet, whatever breed they may belong to, almost invariably have a tan-
coloured spot on the upper and inner corners of each eye, and their lips
are generally thus coloured. I have seen only two exceptions to this rule,
namely, in a spaniel and terrier. Dogs of a light-brown colour often have a
lighter, yellowish-brown spot over the eyes; sometimes the spot is white,
and in a mongrel terrier the spot was black. Mr. Waring kindly examined for
me a stud of fifteen greyhounds in Suffolk: eleven of them were black, or
black and white, or brindled, and these had no eye-spots; but three were
red and one slaty-blue, and these four had dark-coloured spots over their
eyes. Although the spots thus sometimes differ in colour, they strongly
tend to be tan-coloured; this is proved by my having seen four spaniels, a
setter, two Yorkshire shepherd dogs, a large mongrel, and some fox-hounds,
coloured black and white, with not a trace of tan-colour, excepting the
spots over the eyes, and sometimes a little on the feet. These latter
cases, and many others, show plainly that the colour of the feet and the
eye-spots are in some way correlated. I have noticed, in various breeds,
every gradation, from the whole face being tan-coloured, to a complete ring
round the eyes, to a minute spot over the inner and upper corners. The
spots occur in various sub-breeds of terriers and spaniels; in setters; in
hounds of various kinds, including the turnspit-like German badger-hound;
in shepherd dogs; in a mongrel, of which neither parent had the spots; in
one pure bulldog, though the spots were in this case almost white; and in
greyhounds,--but true black-and-tan greyhounds are excessively rare;