CHAPTER XXIII 



THE MARSUPIALS, OR POUCHED ANIMALS 



THE Marsupials, or Pouched Animals, comprise the Opossums, 

 the Dasyures (Tasmanian Devil, Thylacine, etc.), the Wombats, 

 Bandicoots, Phalangers, and Kangaroos. All are characterised by 

 the possession of a pouch or marsupium within which the young, 

 born in a helpless rudimentary condition, are sheltered. They 

 also are distinguished by a pair of peculiar bones attached to the 

 pubes, called the epipubic or marsupial bones. This pouch or 

 marsupium must not be confounded with the temporary pouch 

 of the Monotremes. Its walls are supported by a pair of bones 

 (merely cartilaginous and vestigial in the Thylacine), while within 

 it are the distinct mammary nipples or teats. 



The presence of the pouch or marsupium, containing the teats, 

 involves many structural and physiological peculiarities which 

 separate the Marsupialia, in a classificatory sense, from the rest 

 of the Mammalia. The Great Kangaroo, which may be considered 

 a fair example of the Marsupials, has, in the female, a set of 

 skin muscles around the pouch, beneath the skin, which close it. 

 The milk, or mammary, gland has four long, slender teats in the 

 pouch, and beneath the skin of it is a muscle called the cremaster, 

 which is largely developed; it spreads over the surface of the 

 gland, and its action is to squeeze it and force out the milk through 

 the teat. There is thus protection for the young, and milk is 

 given forth without effort of the young in suckling. The reason 

 for this is obvious. The Great Kangaroo, which is often as tall 

 as a man, is pregnant for about thirty-nine days only, and then 

 a little one, about the size of one's little finger, is born ; a helpless, 

 imperfect little creature, practically a larva, for it has one larval 

 organ in the shape of a special sucking mouth. The mother, 

 with the aid of her lips, places it in her pouch, and it fixes on a 

 teat, where it hangs for about eight months, during which time 

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