r of the family been discovered. The peculiar genus of
Salamander--_Chioglossa_--is quite confined to the Spanish peninsula.

The Butterflies _Nemeobius lucina_ and _Charaxes jasius_ may also have
had their home in that south-western district. To this migration also
seems to belong the genus _Gonepteryx_, which has so peculiar a range in
the British Islands. The only British species, known as the Brimstone
Butterfly (_Gonepteryx rhamni_), occurs in the south of England and in
the south and west of Ireland. It is met with over the greater part of
Europe, and its range extends into Asia Minor and Northern India, and
then it reappears again in distinct varieties in Japan and the Amur
district. Three other species of _Gonepteryx_ are known from Tibet and
India, and one (_G. cleopatra_) from Southern Europe and Northern
Africa. All the remaining species inhabit the west, viz., Brazil,
Mexico, and Venezuela. That the genus has migrated from America eastward
to Europe appears to be more probable than a migration in the opposite
direction. At any rate, that an exchange of species between the
south-western portion of the Holarctic Region and the Neotropical area
took place is indicated by the fact, not only that a variety of _G.
cleopatra_ has been found in Madeira, but also that the Canary Islands
possess a distinct form of _Gonepteryx_, viz., _G. cleobule_.

Dr. Kobelt has given us such an exhaustive memoir on the characteristic
Mollusca of the different zoogeographical provinces of Europe, that we
are particularly well informed as regards that group of Invertebrates.
He tells us that the group _Torquilla_ of the genus _Pupa_--which is a
small chrysalis-like snail--is especially characteristic of the
Pyrenees, Spain, and Portugal. In a certain measure they replace there
the _Clausiliae_ which, as we have seen in the last chapter, have come
from the east and are almost entirely absent in the south-west of
Europe. Of about seventy species of _Torquilla_, the larger number are
confined to this district, and some, which like _Pupa_ (_Torquilla_)
_granum_, range eastward, have travelled along the old Mediterranean
highway, _via_ Algiers, Sicily and Greece, to Asia Minor. They are still
found along the whole of this route.

Similarly, we are told by the same author, that _Gonostoma_--a group of
the large genus _Helix_--has a number of species in the same
south-western district, while only one, viz., _Helix obvoluta_, occurs
in Eng