of external ears, the densely furred feet,
and by the great length of the two middle claws in the fore-feet. There
are two species of the true Lemming, namely, the one just referred to,
_Myodus lemmus_, and _Myodus obensis_. These may be looked upon as more
or less Arctic species, since they occur within the Polar Circle, but
they are not so exclusively confined to that region as the Banded
Lemming (_Cuniculus torquatus_). The remains of both _Cuniculus
torquatus_ and of _Myodus lemmus_ have been found in British pleistocene
deposits.

Until recently no Lemming remains had been found to the south of
France, but Mr. Barrett-Hamilton announced to us a short time since that
Dr. Gadow had discovered some skeletons with their skins still preserved
in a cave in Northern Portugal. These were found to belong to the
Scandinavian Lemming (_M. lemmus_), and the author incidentally
expressed the opinion that there was some possibility of this species
still inhabiting the mountains of Spain.

The Lemming multiplies with great rapidity under favourable conditions.
In speaking of his experiences in Siberia Dr. Brehm says (p. 79): "All
the young of the first litter of the various Lemming females thrive, and
six weeks later at the most these also multiply. Meanwhile the parents
have brought forth a second and a third litter, and these in their turn
bring forth young. Within three months the heights and low grounds of
the tundra teem with lemmings, just as our fields do with mice under
similar circumstances. Whichever way we turn we see the busy little
creatures, dozens at a single glance, thousands in the course of an
hour. But the countless and still increasing numbers prove their own
destruction. Soon the lean tundra ceases to afford employment enough for
their greedy teeth. Famine threatens, perhaps actually sets in. The
anxious animals crowd together and begin their march, hundreds join with
hundreds, thousands with other thousands, the troops become swarms, the
swarms armies. They travel in a definite direction, at first following
old tracks, but soon striking out new ones; in unending files--defying
all computation--they hasten onwards; over the cliffs they plunge into
the water. Thousands fall victims to want and hunger; the army behind
streams on over their corpses; hundreds of thousands are drowned in the
water or are shattered at the foot of the cliffs; the remainder speed
on; other hundreds and thousands fall victims to the