correlation between the eye-spots and the colour of the feet. Moreover,
some jackals and foxes have a trace of a white ring round their eyes, as in
C. mesomelas, C. aureus, and (judging from Colonel H. Smith's drawing) in
C. alopex, and C. thaleb. Other species have a trace of a black line over
the corners of the eyes, as in C. variegatus, cinereo-variegatus, and
fulvus, and the wild Dingo. Hence I am inclined to conclude that a tendency
for tan-coloured spots to appear over the eyes in the various breeds of
dogs, is analogous to the case observed by Desmarest, namely, that when any
white appears on a dog the tip of the tail is always white, "de maniere a
rappeler la tache terminale de meme couleur, qui caracterise la plupart des
Canides sauvages." (1/41. Quoted by Prof. Gervais 'Hist. Nat. Mamm.' tome 2
page 66.) This rule, however, as I am assured by Mr. Jesse, does not
invariably hold good.]

It has been objected that our domestic dogs cannot be descended from wolves
or jackals, because their periods of gestation are different. The supposed
difference rests on statements made by Buffon, Gilibert, Bechstein, and
others; but these are now known to be erroneous; and the period is found to
agree in the wolf, jackal, and dog, as closely as could be expected, for it
is often in some degree variable. (1/42. J. Hunter shows that the long
period of seventy-three days given by Buffon is easily explained by the
bitch having received the dog many times during a period of sixteen days
('Phil. Transact.' 1787 page 353). Hunter found that the gestation of a
mongrel from wolf and dog ('Phil. Transact.' 1789 page 160) apparently was
sixty-three days, for she received the dog more than once. The period of a
mongrel dog and jackal was fifty-nine days. Fred. Cuvier found the period
of gestation of the wolf to be ('Dict. Class. d'Hist. Nat.' tome 4 page 8)
two months and a few days, which agrees with the dog. Isid G. St.-Hilaire,
who has discussed the whole subject, and from whom I quote Bellingeri,
states ('Hist. Nat. Gen.' tome 3 page 112) that in the Jardin des Plantes