ZOOLOGICAL POSITION AND STRUCTURE 9 
never been domesticated, this uniformity of character 
extends to all the individuals. On the other hand, 
when a species has a very large distributional area, 
the individuals inhabiting the localities farthest away 
from one another very frequently differ to a more or 
less marked degree, as they also do from those 
inhabiting the centre of the area. In some cases 
there may be a complete gradation from the typical 
to the aberrant individuals ; but in other instances 
such connecting links may have died out, and it then 
becomes very difficult to say whether all the varia- 
tions should be regarded as referable to a single 
species, or whether one or more of them should 
constitute distinct species. When outlying variations 
are not regarded as worthy of specific distinction, 
they are classed as local races of the species, and 
are then designated by three scientific names. In 
the case of domesticated animals the variation is 
frequently very much greater ; but it is not the 
general practice of naturalists to assign separate 
scientific designations to the various breeds, as the 
variations are called in this instance. In the case of 
the ox only these domesticated breeds remain to us, 
one of these, as already mentioned, forming the 
typical representative of the species. 
Whether the aforesaid local variations in wild 
animals should be regarded as of racial or specific 
value is very largely a matter of individual opinion ; 
and the same is the case with regard to the 
limitations of genera, or assemblages of more or less 
nearly related species. Many naturalists divide the 
members of the ox tribe, which include the extinct 
ox of Europe and its domesticated descendants, the 
humped ox of India and Africa, the bantin of the 
