The phalangers (Phalangeridæ) are a large family found everywhere in Australia. They inhabit the trees, and like most of the marsupials, seek their food at night. They are usually called opossums, but are very different from the genuine opossum of America. Just as the latter are the most perfect and most intelligent of all marsupials, so the Australian opossums are the most perfectly organised of all Australian marsupials. They are, so to speak, the apes of the marsupials, in that they feed on fruit, but are able to live on insects and birds’ eggs; have a prehensile tail and a movable thumb, which almost converts their feet into hands.
Closely related to the latter are the flying-squirrels (Petaurus) which are strikingly like those in India. The smallest one of this family, the beautiful Acrobates pygmæus, is a perfect wonder of elegance and graceful movement. Though not larger than a little mouse, still it flies through the air as skilfully as the larger species. It frequently becomes the prey of domestic cats.
A transition between the kangaroos and the phalangers is found in the marsupial bear (Phascolarctus), while the rodents are represented by the large, plump wombat (Phascolomys).
The family Dasyuridæ are carnivorous. The colonist usually names them after animals of the old world, “marsupial cat,” “marsupial tiger,” “marsupial wolf,” etc. All these marsupial beasts of prey are very rapacious, and one or two of them are quite equal to the martens and weasels in this respect. The marsupial wolf (Thylacinus) and the marsupial devil (Sarcophilus) in Tasmania are the most ferocious and most powerful of all the Australian animals, and do great damage among the sheep. The former is, however, wellnigh exterminated. Native cats (Dasyurus geoffroyi) are numerous everywhere, and are hated by the colonists, because they attack the poultry. Near Mount Elephant, in Victoria, five hundred of them were killed in one night by two poisoned sheep carcasses. There had long been a drought, so that the animals had congregated in the only place where water was to be found.
We now come to the Monotremata, the lowest group of all mammals. They have the marsupial bones, but no pouch, and they are destitute of teeth. Of this remarkable family there are only two genera, the duck-billed platypus and the spiny ant-eater.
The duck-billed platypus (Ornithorhynchus anatinus) is easily recognised by its horny jaws, which have a striking resemblance to the bill of a duck. The animal is about fifteen inches long, and the body, which is covered with close brown hair, is broad, flat, and somewhat like that of a reptile. The feet are short and the toes are webbed. During the daytime the ornithorhynchus sleeps in deep burrows dug in the banks of rivers. It is common in the southern and eastern part of Australia, and is also found in Tasmania.
The spiny ant-eater (Echidna) resembles our porcupine in appearance and size, has quills like it, and can roll itself into a ball. The toes are not webbed, but the animal is a very good swimmer. It feeds on ants and insects, and, like other ant-eaters, has a long, slender tongue, which has a secretion of a sticky substance. It is a most powerful animal, and can disappear so rapidly in loose earth or sand that it seems to sink into the ground. Its flesh is very fat, and is considered a great delicacy by the blacks. On Herbert river, where the ant-eater is called gombian, the natives hunt it with the help of tamed dingoes.
These mammals, the two most remarkable ones on the globe, reveal a wonderful relationship to the lower vertebrates, reptiles and birds. Thus we find that the front extremities are fastened to the breast-bone by a highly developed coracoid and an epicoracoid, as in the case of lizards. This does not occur in any other mammal. Their skulls, like those of birds, have no visible sutures whatever.
The most remarkable fact, however, is that these animals do not bear living young, but lay eggs. The latter contain a large yolk, and when hatched the young are suckled by the mother.
The stages of development of the eggs are different from those of all other mammals, and resemble to a great extent those of reptiles and birds. As the eggs are meroblastic,[[25]] these animals seem to be even more closely related to birds and reptiles than to the mammals.