42 The Humming Bird. 



showing above the surface. This, and their power of sinking 

 noiselessly when alarmed, affords them, no doubt, a means of 

 concealment from the hunter. A somewhat similar case in 

 point is seen in the Crocodiles and Alligators, which look 

 exactly like dead logs laying in the water, especially in their 

 native haunts, when they are surrouiided by slime, water- 

 plants, fallen trunks of trees, etc. A curious means of defence, 

 familiar to everyone, is that of the Hedgehog, which, besides 

 having its body covered with spines, has the power of rolling 

 itself into a ball when attacked, entirely concealing its head 

 and legs (which, with the belly, are the only parts not pro- 

 tected by the spines), and thus becoming nothing but an 

 impenetrable prickly ball. The " fretful porcupine " is another 

 animal protected by spines, these latter being, however, much 

 longer than those of the Hedgehog ; it also differs from the 

 latter by being unable to roll itself into a ball. There are several 

 other animals besides the Hedgehog which possess this power, 

 one of the principal being the Armadillo, a little animal from 

 South America, which is covered with a kind of bony armour 

 on the upper parts of the body and head, and by this means 

 is, when rolled up, as secure from danger as the Hedgehog. 

 There is also a species of woodlouse called the Armadillo, 

 which is frequently met with in England, under the bark of 

 decayed trees, etc., and is armour-plated like the mammal 

 referred to above, rolling itself into a little ball like a black 

 pill when disturbed. Indeed, it is said that the old-time 

 doctors used to have great faith in their virtues as pills, and 

 dried them for the purpose, administering them, along with 

 their powdered snake-skins and other equally delightful pre- 

 scriptions, to their confiding patients. 



An interesting instance of nature's protection is afforded 

 by the Stoat, or Ermine (Mustela erminea). This animal is 

 reddish brown in summer, which colour harmonizes well with 

 the undergrowth in which the creature lives. But, being an 

 inhabitant of northern countries, where snow lies on the 

 ground during part of the year, its summer dress becomes 

 too conspicuous amongst its white surroundings, and its 

 colour then changes to white, which, while effectually con- 

 cealing it from its foes, at the same time enables it to 

 approach, unseen, the small mammals and birds upon which it 

 feeds. It is while it wears this winter coat that it is called 

 the Ermine, and it is then hunted for its skin, which is highly 

 valued. Among birds, the Ptarmigan (Lagopus vulgaris) is 

 one which changes its colour in the same manner as the 



