( Originally Published 1936 )
THE last, but not the least interesting order of mammals, is the Monotremata, distinguished from all the others by the fact that they lay eggs instead of producing living young, and also by their somewhat bird-like beaks, or bills. The eggs have a soft yielding skin like those of a reptile, and are hatched in a kind of pouch like that of the marsupials. The order is confined to Australia and New Guinea, and only a very few species are known.
In this family the body is clothed with hair, the beak is broad and duck-like, and the feet are webbed, and provided with five toes. In habits they are amphibious. The tongue is not prehensile, and the want of teeth is supplied by a horny plate on each side of the mouth.
Duckbill (Ornithorhyncus anatinus)
The Duck-billed Platypus, or Water Mole, as it is variously called, is about eighteen inches in length, including the tail. As the name indicates, the bill bears a close resemblance to that of the common duck, and it is probably used in much the same way to pro-cure its food, consisting of insects, small worms, and so on. The animal is covered with a soft and shining fur, which is reddish-brown above and lighter beneath. The feet are webbed, like those of an otter, and the tail is broad, bristly above, and naked beneath. The Duckbill lives in long burrows which it digs in the banks of streams, and is semi-aquatic in habits. All the toes have claws, and the hind leg of the male is provided with a short thick spur, which the animal probably uses as a weapon of offence. See Plate 40, Fig. 169.
In these animals the body is clothed with fur mixed with strong spines and the beak is rather narrow; there are no horny plates in the mouth, but there are spines on the inside and on more or less of the tongue, which is long and prehensile, as usual in ant-eaters. There are five toes on each foot, not webbed, but armed with claws, and the tail is short.
Spiny Ant-Eater (Echidna aculeata)
This species differs greatly from the duckbill in general appearance. It is not unlike the hedgehog, being covered with spines, and rolls itself up in a ball in the same way when alarmed. The beak is long and delicate, the tongue tapering and extensile, like that of all the ant-eaters, and has spines at the base. See Plate 40, Fig 17o. It is an Australian species, living in open sandy country, and burrowing in the ground with great agility. The food consists of in-sects, especially ants, which it digs out with its claws and licks up with its tongue. Like the duckbill, it lays eggs instead of producing living young.