ORDER IV. RODENTIA. 43 



tail, almost oval in its shape, and covered with scales. It 

 has been supposed that they used this as a kind of trowel, to 

 jay on the mud and clay of which their dikes are partly built. 

 But it has also been sometimes asserted that the tail was only 

 of use as an instrument for swimming. They are aquatic 

 animals, and construct themselves habitations upon waters 

 which are sufficiently deep never to be frozen to the bottom, 

 preferring running streams upon which the trees they cut 

 can float down to whatever spot they have chosen. Here 

 they build a dam for the purpose of preserving the water 

 always of a convenient depth, and construct their huts or 

 cabins. Of their skill, sagacity, and intelligence, a more par- 

 ticular account will be given hereafter. But, although so 

 wonderful in these respects when united in a society, they 

 are, for the most part, helpless and timorous animals when 

 living separately ; a beaver, although pretty large and 'strong, 

 and armed with powerful teeth, if he meets a man alone upon 

 the shore, sets himself down upon his haunches, and "cries 

 like a child. ^ - 



The Jerboa is a little animal of about the size of a rat, with 

 a tail ten inches long, and legs of very unequal size, the hind 

 legs being six inches, whilst the fore legs are but one inch in 

 length. It cannot of course use them all at once without 

 great difficulty, and moves principally by leaps, which are 

 sometimes of five or six feet in extent, or by a hopping motion 

 on its two hind legs, which resembles that of birds. Its fore 

 legs it employs only as hands for the purpose of holding its 

 food. It has been asserted that the ancient cony, mentioned 

 in the Old Testament, was the jerboa, which inhabits Pales- 

 tine to this day. 



There is an American species called the Canadian Jerboa, 

 which does not exceed two and a half or three inches in length. 

 It has the same general characteristics as the animal before ^$-- 

 mentioned, and even exceeds it in the length of its leaps, 

 which extend, if we may credit the accounts given of them, 

 to the enormous distance of three or four yards, or nearly fifty 

 times the length of its body. 



The Hamster is an animal larger and thicker than the Jer- 

 boa, and nearly allied to the common rat. It is distinguished 

 by cheek pouches, which are capable of containing a very 

 large quantity of food. When empty, they are so contracted 

 as not to appear externally visible ; but when filled, they are 

 stretched to an enormous extent, and are capable of contain- 

 ing a gill of grain. A hamster has been caught and dissected, 



