250 uylidm. 



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 typica. 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 (H. 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, in 



