208 DOMESTICATED ANIMALS AND PLANTS 
coyote of the prairie and often with a dash of blood of the 
timber wolf to give energy and ferocity (see Fig. 3). 
A very doglike wild animal is the fox, which, however, 
is not commonly regarded as one of the immediate progeni- 
tors of the common dog on account of structural differences 
in the skull and the more significant fact that the pupil of 
Fic. 35. The dingo, or wild dog of Australia; nearer the domestic dog than 
any other existing wild species 
his eye is elliptical, whereas it is round in the wolf, the jackal, 
and the dog. 
These slight structural differences, however, are counting for 
less than formerly in tracing relationships, and the fact that cer- 
tain South American wolves are very foxlike, as are some of our 
dogs, leads us to be careful in denying the fox even remote 
connection with our domesticated races. 
