Note 9 — Chapter II

There is not a little difficulty in reasoning satisfactorily as to climatal conditions, from the distribution of kindred forms. Even in a single genus there may be a wide range of geographical distribution, so that mere generic identity is not always a safe guide. Thus, the elephant now flourishes in tropical countries, but in the glacial period a long-haired species was abundant in the frozen north. I have above restricted myself entirely to species whose habits and geographical distribution are already sufficiently known.