P. fuscomaculata, an inhabitant of Southern Brazil, Paraguay, and Uruguay, is a short-limbed frog, with spreading slender toes and a small head. There are shovel-shaped, black, horny tubercles on the metatarsus. The general colour is olive above, with darker markings and confluent white-edged spots; the limbs are cross-barred; the lumbar glands are black, with a white margin in front. The male has a vocal sac. Budgett[[95]] gives the following account of its habits:–
The peculiar cry, which is so constantly heard in the neighbourhood of shallow pools in the Paraguayan Chaco, and resembles that of a kitten, is produced by the alternate inflation of throat and abdomen. When fully inflated, the frog appears to be the size of a golf-ball, but, if startled, instantaneously shrinks to one-fifth of that size, so that it seems to have vanished. It has also the power of ventriloquising. The food consists largely of water-beetles. In the spawning time it was found at night floating on the surface of pools in the distended condition, and crying to the females in a most mournful way. On coming to the surface it fills its lungs with a few gasps, greatly distending the walls of the abdomen, and then drives the air into the vocal sacs, causing them to become distended as the body collapses, and giving rise to a kitten-like cry.
The eggs are chiefly laid in January, and are found embedded in a frothy mass floating upon the surface of the water. The eggs measure only 1 mm. and are without pigment, and with extremely little yolk. The larvae become free-swimming within from eighteen to twenty-four hours after the first segmentation. When ready for hatching they wriggle their way through the froth to the water below, and hang into it from the floating froth.
P. biligonigera s. notata, in Brazil, lacks the lumbar gland, the place of which is marked by a black spot. The upper parts are olive, with darker marblings and a dark lateral stripe. The male has a black throat and two external vocal sacs. Hensel found the eggs, in Rio Grande do Sul, in September, forming a frothy mass of the size of a fist, floating between grass upon the water near the margin.
The following three genera may serve as Australian examples, especially since we are indebted to Baldwin Spencer for interesting observations made on their habits in Central Australia.[[96]]
Chiroleptes, of which six species are known, is easily recognised by the first finger, which is opposed to the others. The sacral diapophyses are slightly dilated. The general shape is that of a thick-headed, rather stout land-frog or of a tree-frog. The tympanum is distinct, and the toes are only half webbed, or even less, except in Ch. platycephalus, in which the toes are entirely webbed and the tympanum is indistinct. This species is about 2 inches long, uniformly olive-green above, with a few tubercles on the otherwise smooth skin. Other species rather resemble the European Natterjack in coloration.
Spencer's account is as follows:–"In Central Australia Ch. platycephalus seems to prefer the hard clay pans rather than sandy creeks, as the sand-beds of the latter are too loose for the formation of the burrow. We came across the animal first when encamped by the side of a very shallow clay pan, the floor of which was deeply cracked with the sun's heat. Around the edge were withered shrubs of Chenopodium nitrariaceum, and it was at the base of these that the black fellows looked for the burrow. In the hard-baked clay were imprints made by the frog as it burrowed, and about a foot underground we came across the animal, puffed out into a spherical shape, and just filling up a cavity, the walls of which were moist but not wet. The ground was so hard that it had to be chipped away. When one side of the burrow was opened, the frog remained perfectly still; its lower eyelid was drawn up over the eye and was very opaque, giving rise to the belief amongst the blacks that the animal is blind. In the sunlight, after a short time, it opened its eyes.
"On squeezing the body, water was forced out of the cloaca; this was accumulated principally in the urinary bladder. On cutting the body open it was seen that there was a certain amount of water in the subcutaneous spaces, but that the greater portion, which caused the great swelling-out of the body, was contained in the body-cavity itself; and it was also observed that the lungs were considerably distended and lengthened, their apices lying right in the pelvic region. They contained air and not water, but their outer faces were bathed with the water in the body-cavity." The larvae and tadpoles probably develop with extreme rapidity, soon to aestivate as very small frogs.
Heleioporus has a calcified metasternal plate and slightly dilated sacral vertebrae. The two species have a toad-like appearance, owing to their stout bodies, short limbs and conspicuous parotoid glands. H. albopunctatus is mottled whitish red and brown above; it extends from Western into Central Australia. H. pictus is olive, with darker marblings, and is distinguished by a light vertebral line. It is likewise found in Central Australia, and it extends into Victoria and New South Wales. Spencer found it in swarms after heavy rains, the specimens being much swollen and distended with caterpillars and beetles. They looked as if they were simply gorging themselves with food preparatory to returning again to their long aestivating condition.
Limnodynastes is one of the commonest genera in Australia. The six species have the habits and appearance of stout frogs or smooth toads. L. dorsalis seems to range through the whole of Australia, from east to west, and looks like the European Pelobates. The skin is smooth, but with an elongated white gland extending from beneath the eye to the shoulder, and another glandular complex on the thigh. The upper parts are mottled olive-brown, often with a light vertebral line. The under parts are whitish, with brown spots. The male has a vocal sac. One of the specimens in the National Collection contained a half-grown Heleioporus albopunctatus in its stomach.