DUCKBILL AND ECHIDNA. 



573 



in a mammary pouch, where the young hatch. The duck- 

 bill also lays large eggs. The embryonic development is 

 meroblastic, as in reptiles. The toothless jaws* are long and 

 narrow in the Echidna, or broad and flat in the duckbill 

 (Ornithorlt i/nrJi us paradoxus Blumenbach), where it is cov- 

 ered by a leathery integument; the external ear is wanting. 





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Fig. 494. Skeleton of Echidna hystrix, From Brehm's Thierleben, 



In the aquatic duckbill the feet are webbed, with claws 

 of moderate size. It is covered with a soft fur, and is about 

 half a metre (17-22 inches) long. Its 

 habits are like those of a muskrat, fre- 

 quenting rivers and pools in Australia 

 and Van Di email's Land, sleeping and 

 breeding in holes extending from un- 

 der the water up above its level into 

 the banks, and with an outlet on shore. 

 It lives on mollusks, worms, and 

 water-insects. Young duckbills, five 

 cm. long, have been found in their 

 nests. 



The spiny ant-eater (Figs. 493 and 

 494) is represented by three species, 

 the Echidna hystrix Cuvier, of Aus- 

 tralia, E. Lawesii Ramsay, from Port 

 Moresby, New Guinea, also by a re- 

 cently discovered form inhabiting the 

 elevated portions of Northern New marsupial bones. 

 Guinea, and called by Gervais Acanthoglossus Bruijnii. In 

 these singular animals the bill is long and slender, tooth - 



* Rudimentary teeth occur in the embryo, in the place occupied by 

 the plates (Poulton). 



63 



One half of 

 pelvis of the Kangaroo; m, 



