382 INTEODUCTION TO ZOOLOGY. 



the present period the great metropolis of the order is Austraha; 

 certain species of the group, however, are found in the Molucca 

 Islands, and one genus, containing many species," (the Opos- 

 sums) " is peculiar to the New World." Their remains have 

 been found in a fossil state in Europe, as well as in AustraUa 

 and South America.* 



This order " presents a remarkable diversity of structure, 

 (and consequently habits) containing herbivorous, carnivorous, 

 and insectivorous species ; indeed, we find among the Marsu- 

 pial mammals analogous representations of most of the other 

 orders of mammalia. ' ' Its most striking peculiarity is the pre- 

 mature birth of the young, and consequently the imperfect 

 state of their development at that period. Professor Owen 

 examined the young of the great Kangaroo, twelve hours after 

 birth, and found its whole length from the nose to the end of 

 the tail did not exceed one inch and two lines. t The corre- 

 sponding measurement of a full-grown male would be between 

 eight and nine feet.t 



" An animal so little advanced at the time of its birth as the 

 young Marsupial, requiring a constant supply of food, and so 

 ill fitted to bear the exposure which the more advanced young 

 of other mammaha are subject to, must, it would appear, 

 perish, were not some peculiar provision made for its safety. 

 In the pouch of the female we find this provision." Here the 

 3'oung remain firmly attached to the nipple of the mother, and 

 supplied without effort and in perfect security, with the nutri- 

 ment it requires. " This pouch, when the animal is very 

 young, has its orifice closed, and glued as it were, to the body 

 of the parent by a peculiar secretion. When the young animal 

 is more advanced, this secretion disappears, and the young fre- 

 quently leave the pouch to return at will." 



It has long been a question among naturalists in what man- 

 ner is the young transferred to the pouch ? On this point, an 

 observation made on one of the female Kangaroos, at Knowsley, 

 the seat of the Earl of Derby, gives the first precise informa- 



* Our information is derived from a valuable work now in course of 

 publication, Natural History of the Mammalia, by R. G. Waterhouse, 

 Esq., and when practicable, we give the words of the origiual, marked by 

 inverted commas. 



t A line is the twelfth part of an inch. 



X The body, measured from the tip of the nose to the root of the tail, 

 being, according to Mr. Waterhouse, 63 inches, and the tail 42 inches. 



