20 
ORIGIN OF LIFE IN AMERICA 
of the ancient north Atlantic land connection, and are sup¬ 
posed to have subsequently become extinct on the intermediate 
stations between the two continents, particular attention may 
be drawn to the range of the “ running beetles ” of the genus 
Carabus. They are of great value in aiding us to solve pro¬ 
blems of this nature, because, being usually found under 
stones and clods of earth, they are not liable to occasional 
transport by floods. Being wingless they cannot be carried 
to distant lands by winds ; and lacking any kind of means by 
which they might become attached to a mammal or bird they 
would not be conveyed in such an accidental manner from one 
locality to another. The great importance of the species of 
Carabus has been recognised, and their distribution brought 
to bear upon zoogeographical problems by Mr. Born.* He cites 
two of the species, viz., Carabus catenulatus and Carabus 
nemoralis, as evidences of a former land bridge between 
northern Europe and North America, although they no longer 
occur in Iceland or in Greenland. Both these running beetles 
are typically European species, being quite absent from Asia. 
The conspicuously ornamental Carabus memoralis is confined 
in North America, to Nova Scotia and New Brunswick. Hence 
it somewhat agrees in its American range with that of Helix 
hort-ensis. The other species of Carabus has a wider dis¬ 
tribution in boreal North America. 
Such instances lead us to believe, therefore, that the faunas 
of Greenland and Iceland were richer in pre-Glacial times 
than at present. They are certainly suggestive also of a sur¬ 
vival of species having taken place through the Ice Age within 
the glaciated area of North America. We possess no evidence 
that these beetles and the snail Helix hortensis, and many 
other animals belonging to the same group of European in¬ 
vaders, were pushed south during Pleistocene times into the 
United States, and that they then regained their former 
northern habitat, after having become extinct again in their 
more southern stations. 
The extinction of a large part of the former beetle fauna 
of Greenland may be inferred from the fact that Greenland 
only possesses forty-one species of beetles, while there are 
* Born, P., “ Zoogeographisch-carabologische Studien,” p. 8. 
