PHYSIOGRAPHY OF AUSTRALASIA. 



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shape also, and in the limited districts to which it is now restricted is the cause of 

 much damage to the flocks. Both of these animals are found only in Tasmania, while 

 the native cats occur in all the Australian colonies. 



In spite of the great diversity which they exhibit in external form and in mode of 

 life, the marsupials are all connected together, and distinguished from other mammals by 

 certain points in their structure, 

 which, for the most part, mark 

 them as somewhat lower in the 

 scale of animated nature. The 

 most prominent general feature 

 of the marsupials is the pouch, or 

 iiiarsnpiuni, from which the name 

 of the order is derived. This is 

 a pouch of skin on the lower 

 surface of the female, in which 

 the teats are situated, and in 

 which the young, born in a very 

 weak and helpless condition, are 

 protected and nourished. 



The duck-bill platypus and 

 the echidna are the most remark- 

 able of all the Australian mam- 

 mals. In many particulars of their 

 anatomy they differ from all other 

 members of the class Mammalia, 

 and approach nearer to the rep- 

 tiles. Hut they possess those dis- 

 tinctive organs of the Mammalia 

 the mammary or milk glands which 

 no other animal but a mammal 

 possesses. The milk glands, how- 

 ever, which the echidna and platypus possess are of a very undeveloped type, and, 

 though large, they have no teats the milk passing out through a number of fine pores, 

 which perforate a bare patch of skin, and collecting in a little cup-like depression. Though 

 the platypus and echidna thus, in a sense, suckle their young, they yet, unlike all other 

 mammals, lay eggs, the development of which in their early stages resembles that of the 

 e S s f reptiles and birds, rather more than that of the ova of mammals. These two 

 peculiar Australian animals together constitute the Monotrcinata, the lowest order of the 

 mammals, not represented either by living, or, so far as our knowledge extends, by 

 fossil forms in any other quarter of the globe. 



Though nearly related to one another in their essential structure, the platypus and 

 the echidna are widely different in outward appearance and mode of life. The platypus 

 (Ornithorhynchus paradoxns), is found in quiet pools, in creeks, rivers, and in lagoons 

 throughout the southern half of Australia. It has a somewhat flattened body with short 



LEADBEATEK S COCKATOO. 



