ORDERS OF MAMMALIA. 289 



chiefly of aquatic insects and mollusks, and they make very 

 extensive burrows in the banks of streams. 



FIG. 142. Monotremata. Duck -mole (Ornitliorhynchus paradoxus). 

 (After Waterhouse.) 



The other member of the Monotremata is the Porcupine 

 Ant-eater or Echidna, which is not unlike a large hedgehog 

 in appearance. The snout is very long, and is enclosed in a 

 continuous skin till close upon its extremity, where there is a 

 small aperture for the protrusion of a long and flexible tongue. 

 There are no teeth, nor any organs to act as teeth. The feet 

 have five toes each, and are furnished with strong digging- 

 claws, but the toes are not webbed. The skin is covered with 

 strong prickly spines interspersed with bristly hair. The 

 Echidna measures from fifteen to eighteen inches in length, 

 and is a nocturnal animal. It lives in burrows, and feeds 

 upon insects, which it captures by protruding its long, sticky 

 tongue. 



ORDER II. MARSUPIALIA. The name of Marsupials is de- 

 rived from the fact that the females of this order are mostly 

 furnished with an abdominal pouch or marsupium, within 

 which the nipples are situated. When born, the young are 

 placed by the mother within this pouch, where they adhere to 

 the teats, and can be carried about without injury. Even 

 when further advanced in their development, the younor often 

 betake themselves to the shelter of the marsupium. The so- 

 called "marsupial bones" are present, and as they spring 

 from the front of the pelvis they no doubt serve to support the 

 pouch ; but this cannot be their sole use, as they exist in the 

 males, and also' in the Monotremes, in whom there is no pouch. 

 All Marsupials possess teeth, and the pectoral arch has now 

 the same form as in the higher Mammals, the coracoid bones 



