CHAP. XIX.] 
THE MADAGASCAR GROUP. 
393 
southward along the Andes into South America. Tapirs are 
even more interesting and instructive. Their remotest known 
ancestors appear in Western Europe in the early portion of the 
Eocene period ; in the later Eocene and the Miocene other 
forms occur both in Europe and North America. These seem 
to have become extinct in North America, while in Europe 
they developed largely into many forms of true tapirs, which at 
a much later period found their way again to North, and thence 
to South, America, where their remains are found in caves and 
gravel-deposits. It is an instructive fact that in the Eastern 
continent, where they were once so abundant, they have 
dwindled down to a single species, existing in small numbers 
in the Malay Peninsula, Sumatra, and Borneo only ; while in 
the Western continent, where they are comparatively recent 
immigrants, they occupy a much larger area, and are repre- 
sented by three or four distinct species. Who could possibly 
have imagined such migrations, and extinctions, and changes of 
distribution as are demonstrated in the case of the tapirs, if we 
had only the distribution of the existing species to found an 
opinion upon? Such cases as these — and there are many others 
equally striking — show us with the greatest distinctness how 
nature has worked in bringing about the examples of anomalous 
distribution that everywhere meet us ; and we must, on every 
ground of philosophy and common sense, apply the same method 
of interpretation to the more numerous instances of anomalous 
distribution we discover among such groups as reptiles, birds, 
and insects, where we rarely have any direct evidence of their 
past migrations through the discovery of fossil remains. When- 
ever we can trace the past history of any group of terrestrial 
animals, we invariably find that its actual distribution can be 
explained by migrations effected by means of comparatively 
slight modifications of our existing continents. In no single 
case have we any direct evidence that the distribution of land 
and sea has been radically changed during the whole lapse of 
the Tertiary and Secondary periods, while, as we have already 
shown in our fifth chapter, the testimony of geology itself, if 
fairly interpreted, upholds the same theory of the stability of 
our continents and the permanence of our oceans. Yet so easy 
