126 VERTEBRATES. 



and increasing in size, until they are as completely formed as otliei 

 animals are at the time of their birth. So small in proportion are 

 the young when first born, that the kangaroo, which, when full 

 grown, is as large as a sheep, and weighs one hundred and fifty 

 pounds, is at its birth no more than an inch in length, and weighs 

 only twenty-one grains. 



Generally, the female is furnished with a duplicature of the 

 skin of the abdomen, which forms a kind of bag, coTering the 

 nipples, in which it places its young, and preserves them during 

 the period of helplessness. Frequently, indeed, even after they 

 have acquired strength to leave this pouch, they retreat into it 

 upon the approach of danger. Sometimes, in place of the pouch, 

 there is simply a fold of the skin. The pouch is supported by 

 means of two bones attached to those of the pelvis, from which 

 proceed muscles that open or contract its mouth, like the opening 

 of a purse. These bones are found also in the male, and in those 

 species which have not the complete pouch ; and are always an 

 indication that the animal belongs to this order. 



The Great Kangaroo inhabits New Holland and Van 

 Diemen's Land. Its length is about five feet without the tail, 

 which measures about three feet. Its singular formation, pecu- 

 liarly adapted to the country, 

 calls forth a corresponding de- 

 gree of ingenuity on the part 

 of the natives, who live much 

 on its flesh. Its method of 

 progression is by immense leaps 

 from its long hind legs, assisted 

 by its tail. The length of each 

 leap is about fifteen feet. Of 

 course this swiftness would soon leave its pursuers behind, but tho 

 Australian is able to break one of its limbs or strike it insensiKle 

 to the ground with his boomerang, the most wonderful weapon 

 that uncivilized man ever produced. This extraordinary missile 

 is a flat curved piece of wood, which the Australian natives can 

 wield with wonderful skill, making it describe circles in the air, 



