308 NATURAL HISTORY. 



The ondatra, or musk-rat of Canada, differs from 

 the desman in having its toes all separated from each 

 other, in having eyes very conspicuous, and a very 

 short snout. The desman or musk-rat of Muscovy, 

 on the other hand, has the toes of its hind feet united 

 by a membrane. The tail of both is flat ; and not 

 only in this circumstance, but in a number of essential 

 characteristics, they differ from the pilori, or musk-rat 

 of the Antilles. 



The ondatra is of the size of a small rabbit, and of 

 the form of a rat. Its head is short, and similar to 

 that of the water-rat ; its hair is soft and glossy, with 

 a very thick down underneath, nearly like that of the 

 beaver. Its tail is long, and, though of a different form, 

 covered with little scales, in the same manner as those 

 of other rats. Its ears are very short, but not bare, 

 like those of the (fomestic rat. 



The striking singularities which have been remark- 

 ed in the ondatra, are, the force and great expansion 

 of the muscles of the skin, the suppleness of the false 

 ribs, which permits so considerable a contraction of the 

 body, that the musk-rat is known to obtain an easy en- 

 trance into holes too narrow for the admission of ani- 

 mals much smaller than itself. The manner too in 

 which the female voids her urine is a very striking 

 characteristic ; the urethra not terminating, as in 

 other quadrupeds, but at a hairy eminence situated 

 over the ospubis : the testicles also, which, as in other 

 rats, ae situated on each side of the anus, become pro- 

 digiously large while the ardour for propagation lasts. 

 Add to these that the vessels which contain the musk 

 or perfume of this animal, under the form of a milky 

 humour, and which adjoin to the parts of generation, 

 undergo the same changes ; that, during the rutting 



