108 SUBIUNGDOM VERTEBKATA. 



Didelphidse. The Opossum belongs to this Continent, 

 but of the thirty species, only one is found in North Amer- 

 ica. The common variety is about the size of a cat, with a 

 pointed head ; large, naked ears ; sharp teeth ; rough tongue ; 

 long, prehensile tail ; and curved claws.* It is mostly noc- 

 turnal and arboreal, and both herbivorous and carnivorous. 



ORDER MONOTREMATA. 



General Characteristics. The Monotremes, found 

 only in Australia and vicinity, form a connecting link 

 between the Mammals and Birds. 



The Porcupine Ant-eater has a nearly cylindrical beak 

 covered with skin, except at the end, where there is a small 



Fig. 181. 



Echidna hystrix^ Porcupine Ant-eater. |. 



opening for its long, flexible tongue. It has no teeth, and 

 feeds on insects. Its body is covered with hair and spines. 

 When surprised, it rolls itself into a ball, or burrows flatwise 

 into the earth with surprising rapidity. 



* Hunting the animal is a favorite sport in some of the Southern States. In the 

 bright moonlight evenings of the autumn, parties go out for this purpose with dogs. 

 The opossum soon hides in the thick branches of a tree ; but, when shaken down, rolls 

 into a hall and feigns itself dead ; after a few moments it slowly opens one eye, 

 then the other, and if unhindered sneaks away. The young weigh only about four 

 grains when put in the pouch, and are blind and deaf. Within a week Iheir tails 

 become prehensile enough to twine around one another's bodies. In five weeks they 

 are able to crawl out and are sometimes found on the back of the mother, with their 

 tails grasping hers, which, in turn, is twisted about a branch. 



