CHAPTER XXII 



THE ECHIDNA AND THE DUCK-BILLED PLATYPUS 



THE Mammalia are the highest of the Vertebrata, and comprise 

 the Monotremes (the animals about to be described), the Marsupials 

 (pouch-bearing Mammals), the hoofed and clawed quadrupeds, 

 the Whales, Porpoises, and Sea-Cows; the Rodents, Bats, and 

 Insectivores (Moles, Shrews, and Hedgehogs), the Lemurs, Apes, 

 and Human species. All are air-breathing throughout life, though 

 many lead a truly aquatic existence. The blood has a high tem- 

 perature, and, with the exception of the Monotremes, the mammary 

 glands are provided with teats. All, except the Monotremes, are 

 viviparous. The scales of the reptiles and the feathers of birds 

 are replaced in the Mammalia by special epidermal structures, the 

 hairs usually so abundant as to form a thick soft coating of fur. 



The Monotremes are Mammals without teats, but with a 

 temporary pouch developed during the breeding season, in which 

 the young are hatched, or to which they are transferred after 

 hatching, and into which the ducts of the mammary glands open. 

 This pouch is considered to be the equivalent of a teat, and not 

 of the pouch of the Marsupials. 1 The milk glands communicate 

 with the exterior by a number of small pores situated in a cup- 

 like depression in the skin of the abdomen. The Monotremata 

 are represented to-day by two families, (i) the Ornithorhynchus, 

 or Duck-billed Platypus, sometimes also called the Water Mole ; 

 and (2) the Echidna, the Spiny or Australian Ant-Eater, animals 

 which, in addition to the remarkable traits already described, show 

 in their skeleton numerous ancient characteristics. 



The Echidna is about a foot long, and the upper part of its 

 short body is covered with strong spines, the rest being hairy, 

 while the front of the head and the long tapering snout are naked. 

 The legs are short and strong, and the toes of the foreleg are armed 



1 Jb\ E. Beddard. 



