202 MOSTLY MAMMALS 
many parts of Europe the wolf-dogs and sheep-dogs are 
remarkably like the races of wolves inhabiting the same 
districts ; and the black Florida wolf-dog is strikingly similar 
to the black wolf of that country. Sheep-dogs may there- 
fore be included among the breeds descended from wolves, 
and are some of those which have undergone the least 
amount of modification from the parent type. On the 
other hand, when we proceed to South-Eastern Europe 
and the South of Asia, we meet with breeds of dogs so 
like the jackals of the same districts that it is hard to 
believe they are not very closely related. South Africa 
is the home of that very peculiar species, the black-backed 
jackal, and in many districts dogs are met with showing 
a marked resemblance in form and coloration to that 
species, although having lost the deep black patch on the 
back from which it takes its name. It has also been 
noticed that certain domesticated breeds in South America 
are so like the Canis azarae of the same region as to lead 
to the belief that the one is the descendant of the other. 
From these and other considerations Darwin was led to 
the following conclusion: “It is highly probable that the 
domestic dogs of the world are descended from two well- 
defined species of wolf—namely, C. /upus and C. latrans— 
and from two or three doubtful species—namely, the 
European, Indian, and North African wolves; from at 
least one or two South American canine species; from 
several races or species of jackal; and perhaps from one 
or more extinct species.” 
In all the above-mentioned instances the domesticated 
breeds belong either to half-savage races, or are those 
which, like wolf-dogs, sheep-dogs, and pariah dogs, have 
departed but little from the original wolf or jackal type. 
In some cases we have seen these breeds are kept true 
