300 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



hair of the abdomen and licked off by the young. The duck- 

 bill or platypus, genus Ornithorhynchus, is about sixteen inches 

 long, has webbed feet, close water-proof fur, and a flattened 

 duck-like bill. It lives mostly in water, with an underground 

 chamber leading from the water, in which the eggs are laid and 

 the young reared. The spiny ant-eater, genus Echidna, lives 

 in burrows, and feeds, by means of a long snout bearing the 

 toothless mouth and extensile tongue, on ants. Its eggs are 

 carried in a skin pouch on the abdomen. 



The order Marsupialia includes the kangaroos, opossums, 

 and others. These differ from all other mammals in that the 

 female has an external pouch, or marsupium, in which the young 

 are placed after birth and carried about and nourished until 

 they are more fully developed. As these animals have no 

 placenta, by means of which the young may be nourished by 

 the blood of the mother, they are born in a very helpless 

 condition and so must be cared for in the marsupium for some 

 months. In Australia most of the land animals are marsupials. 

 The kangaroos are the most familiar examples. They were 

 formerly quite abundant, but have been hunted for their skins 

 to make leather for shoes until their numbers have been much 

 reduced. The opossum, Didelphys virginiana, which is the 

 only North American representative of the order, lives in trees, 

 is about the size of a common cat, and has a dirty-yellowish 

 woolly fur. Its tail is long and scaly, like a rat's. Its food 

 consists chiefly of insects, although small reptiles, birds, and 

 bird's eggs are often eaten. When ready to bear young the 

 opossum makes a nest of dried grass in the hollow of a tree, 

 and produces about thirteen very small (half an inch long) 

 helpless creatures. These are then placed by the mother in 

 her pouch. Here they remain until two months or more after 

 birth. Probably all the North American opossums found from 

 New York to California and especially common in the Southern 

 States, belong to a single species, but there is much variety 

 among the individuals. They are commonly used for food 

 and are sometimes seen on the market. 



The order Edentata includes the sloths, armadillos and ant- 

 eaters, all found in tropical regions. The sloths dwell in the 



