P. cultripes.–This is the Spade-foot of the whole of Spain and Portugal and of the southern and western parts of France. It is similar in habits to P. fuscus, from which it differs but slightly. The tarsal spur is black, and there is a parieto-squamosal bridge which completely roofs over the temporal fossa and closes the orbit behind.–Boulenger has discovered the rare, individual occurrence of minute teeth on the parasphenoid and on the pterygoids of this species. These teeth are unquestionably the last reminiscences of a condition almost entirely superseded in the recent Anura.
P. syriacus from Asia Minor and Syria agrees with P. cultripes in the cranial configuration, but has the yellow or brown spur of P. fuscus.
Fig. 33.–Pelobates cultripes, Spade-foot Toad, × 1, and under surface of left foot.
Scaphiopus.–The Spade-foot of North America and Mexico differs slightly from those of Europe, chiefly by the presence of a more or less hidden tympanum and of a subgular vocal sac, and by the sternum, which forms an entirely cartilaginous plate without a special style. The close relationship of these two genera is further indicated by the occurrence of peculiar large glandular complexes in some of the species, pectoral in S. solitarius, tibial in S. multiplicatus of Mexico. At the same time this genus approaches Pelodytes.–About eight species are known, two of which inhabit the United States, the others Mexico.
S. solitarius is the commonest species of the Southern States. It is brown above, with darker patches; its total length is about 2 inches. According to Holbrook it excavates small holes half a foot deep, in which it resides, seizing upon such unwary insects as may enter its dwelling. It never leaves the hole except in the evening or after long-continued rains. It appears early in March, and soon pairs; as an instance of hardiness Holbrook mentions that he has met it whilst there was still snow on the ground. When teased they assume a humble attitude, bending the head downwards with their eyes shut, as illustrated by Boulenger.[[78]]
Pelodytes is, like the rest of the genera, devoid of the tarsal digging spur. The tympanic disc is rather indistinct; the male has a subgular sac. The general appearance of the slender body with long hind-limbs and toes is frog-like. Two species only are known, one in South-Western Europe, the other in the Caucasus.
P. punctatus.–The "Mud-diver" has the upper parts covered with small warts, and is about 1½ inch in length. Its coloration is variable, and changes much. One day it may appear greenish brown, the next day pale grey; in the daytime perhaps with many bright green spots, and in the evening spotless and unicoloured. The under parts are mostly white, sometimes with a fleshy tinge. The male has a voice like "kerr-kerr" or "creck-creck," uttered during the breeding season, which lasts from the end of February until May, according to the temperature and the more Southern or Northern locality. Occasionally they breed a second time in the summer or autumn. The male develops nuptial excrescences, chiefly three rough patches on the inner side of the fore-limbs or on the inner side of the first two fingers, while the belly and thighs are covered with small granules. In the mode of copulation, the laying of the small and numerous eggs, the hatching of the larvae in a tail- and gill-less condition, this genus closely resembles Pelobates; but the tadpoles never reach a colossal size, the usual length being 2 inches, and even this is comparatively large for so small a species. It inhabits the greater part of France, most of Portugal, and the southern half of Spain, avoiding, however, the central plateaux and the mountain-ranges. Its habits are essentially nocturnal, living in the immediate vicinity of the water, into which it hops with a long jump in order to hide in the mud. Easily kept, it breeds regularly in captivity, according to circumstances at almost any time of the year.
P. caucasicus has been discovered in the Caucasus at an altitude of 7000 feet. The remaining genera of this family contain only a few species each, and are restricted to South-Western Asia, the Malay and Papuan Islands. The commonest is Leptobrachium, which ranges from the Himalayas to Borneo and Java. Pupil vertical. Vomerine teeth sometimes absent. Tongue roundish, very slightly nicked behind. Tympanum indistinct. Omosternum small, cartilaginous. Male with internal vocal sacs. Tarsus with a roundish tubercle. Some of the species, e.g. L. carinense from the Karen Hills, attain to a large size, namely, 6 inches; they seem to live on rats and mice, and one specimen contained a young squirrel.
Fam. 3. Bufonidae (Toads).–The formula:–no teeth in the upper and lower jaws, vertebrae procoelous and without ribs, sacral diapophyses dilated,–is sufficiently diagnostic of this cosmopolitan family. The generally entertained notion that toads have a rather thick-set, short-limbed, warty appearance, does not apply to all the members of the family. The majority are quite terrestrial, many are burrowing, the Javanese Nectes is aquatic, the Afro-Indian Nectophryne is arboreal, while the Australian Myobatrachus and the Mexican Rhinophrynus eat termites and are correspondingly modified; lastly, Bufo jerboa is a slender, long-legged creature.