File:The tailless batrachians of Europe (Pl. XIV) (8164092383).jpg

250 hylim.
Geographical Variations. — This species may be
divided, from the permanent markings, into a number
of more or less defined varieties, each of which has a
distinct habitat.
1. Forma ti/pica. A greyish, brown, or black streak,
edged above with yellow or white, extends from the
nostril through the eye and the tympanum along the
side of the body, sending upwards and forwards a
branch on the loin

a whitish line on the upper lip,
descending to the shoulder, and then ascending to the
eye, limiting an elongate green area behind and below
the commissure of the jaws

a dark, light-edged cross-
line above the vent

the outer side of the fore-arm,
carpus and fourth finger, tibia, tarsus, metatarsus,
and fifth toe with a more or less distinct dark and
light edge.
This is the most widely distributed form in Europe,
inhabiting the greater part of the continent and ex-
tending into Asia Minor.
2. Var. savignyi, Aud. (japonica, Gthr.). Similar
to the typical form, but the marking on the loin is
absent, or distinct from the lateral streak, which is
frequently broken up into spots from the middle of
the side.
Inhabits Corsica, Elba, Sardinia, the Greek Archi-
pelago, South-western Asia, Lower Egypt, Corea,
China, and Japan.
Allusion has been made in the Introduction to the
great facility with which the common tree-frog not
only changes colour, but also puts on temporary dark
or light spots, which greatly alter its appearance.
In this variety, however, we find specimens with large
dark spots or stripes on the back and cross-bars on
the limbs, which appear to be permanent, and owing
to which these frogs have been regarded as distinct
species (77. japonica, Gthr., H. sarda, Bonelli). Such
specimens are more frequent in China and Japan,
but also occur, though in lesser abundance than and
promiscuously with unspotted ones, in Corsica,