124 CLASS MAMMALIA. 



which supply and receive from the lungs. He also found 

 the lungs, the veins of the neck, head, and especially of 

 the brain, considerably distended with blood. 



The common Dormouse is found, though not very plenti- 

 fully, in England. 



We insert a figure of the Muscardin Dormouse, (Mus 

 Avellanarius, Lin.) but shall add nothing here to its specific 

 characters, as stated in the Table. 



The subgenus Hydromys includes at present, perhaps, 

 but a species sometimes found with a white belly {Hydromys 

 leucogaster), and sometimes with a yellow belly {Hydromys 

 chrysogastef) ; these, however, are specifically separated by 

 their describer. 



The animals proper to this subdivision approach the 

 characters of the Dormouse and the Rat, by their teeth on 

 the one hand, and the Water-Rat and the Beaver, by their 

 aquatic habits, on the other. 



The Hydromys is about a foot long, and the tail is nearly 

 the same length ; the colour is brown above, and orange- 

 colour or white underneath ; the tail is covered with short 

 rough hair, thick at the base, and of the same colour as the 

 belly ; the colour then becomes blackish as it approaches 

 the end, but the tip is quite white. 



We are perfectly ignorant of the habits and manners of 

 these animals, nor is their habitat very accurately known, 

 though they appear to belong to the western coast of New 

 Holland. 



We have seen by the text that the Coypus of America is 

 placed, though conditionally by the Baron, in the subdi- 

 vision Hydromys. Subsequent observation has determined 

 that its characters are so far distinct as to separate it into a 

 new subgenus, as proposed by Commerson, which he has 

 named Myopotamus. As the teeth constitute its principal 

 pretensions to a generic separation, and they are noticed in 



