_E. clamata_ s. _fontinalis_, likewise an inhabitant of Eastern North America, may be called a smaller edition of the Bullfrog, its usual full-grown size being about 3½ inches. The tympanum is conspicuously large, but the toes are webbed to a lesser extent, and the skin forms a glandular fold which extends from the shoulder in a curve to the flank. This species is partial to the neighbourhood of running streams; it is said to be {263}exceedingly timid, and to utter a short cry when disturbed and making its enormous leaps. Another North American relation is _R. halecina_ s. _palustris_, frequenting the neighbourhood of ponds and rivers, very lively and capable of jumping 8 to 10 feet. The tympanum is smaller than the eye, but there is the same glandular lateral fold as in _R. clamata_. The vocal sacs are internal and decidedly small. [Illustration: FIG. 50.–_Rana clamata_, × ⅔.] _R. esculenta._–The common Water-frog of nearly the whole Palaearctic region is closely allied to the American Water-frogs described above, and, like most of them, has the vomerine teeth in two small oblique rows between the choanae and extending a little beyond their posterior border. But the males have a pair of external vocal sacs. The tympanum is distinct, about two-thirds the size of the eye. The first finger is slightly longer than the second. The toes are entirely webbed. Besides the usual subarticular phalangeal tubercles, the sole of the foot is provided with two metatarsal tubercles, the outer of which is very small, while the inner is much larger, although varying in size from a soft oval to a long, curved, shovel-shaped structure. The skin is smooth, except for a pair of prominent glandular folds which extend from behind the eye along the dorso-lateral line. The coloration varies considerably. The upper parts are mostly greenish brown, with black brown spots on the back, and larger patches on the limbs. Most specimens have three lighter stripes along the back, the middle one mostly green, the two lateral bronzy brown and coinciding with the glandular folds. The tympanum is brown, and there is occasionally a dark temporal patch. The posterior aspect of the thighs is invariably {264}spotted with black and white or yellow, in opposition to the _R. temporaria_ group, where these parts are never spotted. The total length of this species varies much. Specimens 2½ inches in length are certainly mature, those of 4 inches are unusually large, and Boulenger has received a giant from Damascus, which measured 125 mm., or nearly 5 inches. The females are larger than the males. The variations in colour are not only local but also individual, moreover the colours are changeable. The ground-tint ranges from dull brown through olive to bright green, the dark spots being more or less pronounced and numerous; the light vertebral line is olive-yellowish, bright green, or altogether absent.