NATURAL HISTORY AND DISTRIBUTION OF BEARS. 
259 
tended further southwards ; moreover, as just observed, the same 
is applicable to Great Britain and Ireland. Thus through 
mutations in the relative conditions of sea and land we find that 
many species accustomed to roam over vast tracts of country 
became restricted to small islands ; and to the bear tribe, of all 
others, this would be trying to their constitutional habit of 
wandering from place to place ; add thereto new climatic con- 
ditions, consequent on the geological changes, and we may 
fairly believe that modifications not only in the habits, but also 
the outward appearance and internal anatomy would ultimately 
result, so that the cabinet naturalist, trusting to bodily appear- 
ances as represented by specimens from various regions, is apt 
to assign distinctive characters to what are merely varieties of 
one species. 
