THE OVERLAPPING-CHESTED TREE FROGS 2645 



the webbing of the hind-toes; while there is a fold on the ankle, and the tubercles 

 on the joints of the lower surface of the hind-toes are to a large extent double. The 

 hind-limb is unusually short; the flattened warts on the back are distinctly porous; 

 the glands behind the eyes are small, depressed, and either oval or triangular; and 

 there is an additional gland on the leg. The general color of the upper parts is 

 light olive, with darker marblings or spots, the above-mentioned light line being 

 generally present; while the light under parts are more or less spotted with black. 

 In its movements the natterjack is less sluggish than the common toad, its pace be- 

 ing often quickened to a kind of run, during which the body is raised considerably 

 above the ground. It is likewise less intolerant of drought, being frequently found 

 in hot, sunny situations, and only resorting to the neighborhood of water during the 

 breeding season. 



The Mexican sharp-nosed toad (Rhinophrymis dorsalis), already re- 

 ferred to as subsisting on white ants, is the only other member of the 



1 O3.G 



family that we have space to mention, and is generically distin- 

 guished by the long and narrow tongue being free in front, by the vertical pupil of 

 the eye, and by the rudimentary breastbone. The front-toes are free, and those of 

 the hind-limb webbed, with simple tips; while the general form of the body is ex- 

 tremely stout; the head small, with a long, truncated muzzle and narrow mouth; the 

 eyes being small, and the limbs remarkably short. In color this toad is olive brown 

 or bluish gray above, frequently with yellowish spots on the flanks and middle of 

 the back, those on the back sometimes uniting to form a line. 



THE OVERLAPPING-CHESTED TREE FROGS 

 Family HTLIDsE 



The numerous, mostly arboreal, frogs thus designated form a family compris- 

 ing some ten genera, very abundant in Australia and America, and more sparingly 

 represented in Europe, Asia north of the Himalayas (one species ranging into 

 Northeastern India and Burma), and Northern Africa. While resembling the toads 

 in the expansion of the processes of the sacral vertebra, they differ by the presence 

 of teeth in the upper jaw, and they are peculiar in the claw-like form of the 

 terminal joints of the toes. The vertebrae are cupped in front, and spherical be- 

 hind, and there are no ribs. 



The grasshopper frog (Acris gryllus] of North America is the sole 



representative of a genus characterized by the horizontal pupil of the 



eye, the webbing of 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 



