280 
FROGS AND TOADS. 
the hind-toes, of which the tips are but little expanded, and the slight expansion 
of the processes of the sacral vertebra. In form this little frog is slender, with a 
narrow head and rather sharp muzzle; while the skin of the upper-parts is either 
smooth or slightly tuberculated, and that of the under-parts granulated. The 
mottled and striped coloration is very variable, the ground-tint ranging from 
reddish brown to green; but there is generally a large, triangular, dark brown 
spot between the eyes, and sometimes a light stripe down the back. Locally very 
abundant in Eastern and Central North America, the grasshopper-frog derives its 
name from its piercing, strident cry, which resembles the noise of its insect name¬ 
sake. It frequents stagnant waters, and is fond of resting on the leaves of 
aquatic plants. Unlike most of its allies, it lurks among plants, and seldom, if 
ever, ascends bushes or trees. 
Typical Tree- Closely allied to the last are the numerous species of typical 
Frogs. tree-frogs ( Hyla ), which are by far the most beautiful representatives 
of the entire order, and are best known by the common European species. In this 
genus the pupil of the eye is horizontal, the toes of both limbs dilated into discs, 
and those of the hind-foot more or less extensively webbed, the tongue either 
adherent or more or less free behind, and the expansion of the transverse pro¬ 
cesses of the sacral vertebra more or less strongly marked. As in the last genus, 
there are teeth on the vomers. Represented by about one hundred and fifty 
species, this genus has a distribution coextensive with that of the family; the sole 
Indian member of the latter being included. The under surface of their bodies is 
very different to that of the terrestrial species; for the skin, instead of being 
smooth, is covered with granular glands, pierced by numerous pores, through 
which the dew or rain, spread on the surface of the leaves, is rapidly absorbed 
into the system, and reserved to supply the moisture necessary for cutaneous 
respiration. Except during the breeding-season, when the greater number of them 
seek the water, or when they retire before the cold of winter or drought of summer 
under mud, beneath stones, the bark of trees, or in other safe spots, these frogs spend 
their lives among the leaves of trees, where they find alike their dwelling-places 
and their hunting-grounds. As in the case of the flying frogs, their colour har¬ 
monises exactly with their natural surroundings, and changes even more rapidly 
than that of the chainseleons. So exactly indeed do they resemble the foliage 
among which they hide, that it is often difficult to tell frogs from leaves; and it 
has been noticed that where there is the greatest variety and brilliancy of colour 
among the forest trees, the tree-frogs attain their most brilliant and varied tints. 
The European tree-frog ( H . arborea), which is one of three species inhabiting 
the Old World proper, lias a wide geographical distribution, inhabiting the greater 
part of Europe, Asia north of the Himalaya as far east as Japan, and North Africa. 
With the exception of the higher mountain ranges and the extreme north, as well 
as Norway and Britain, it is spread over the whole of Europe, although varying 
locally to a considerable degree in coloration and habits. The males are furnished 
with a large external vocal sac on the throat, and the skin is smooth above and 
granulated beneath. The general coloration may be described as greenish above, 
and uniform whitish beneath, but there are many variations in regard to the 
markings on the upper-parts; the typical form having a greyish or black light- 
