Swaps in Natural History. 247 



Didelphidai. 



18. Didelphis Virginiana, Opossum. 



RoDENTIA. 



Casioridce. 



19. Castor fiber, Harlan, Beaver. 



20. Fiber zibethicus, Desm., Muskrat. 



Leporidce. 



21. Lepus Americanus, Lab., Hare. 



MuridcB. 



22. Arvicola xanthognata, Leach, Meadow Mouse. 



23. A. riparius, Ord. in Godman, Marsh Mouse. 



18. The opossum is rare; his favorite food, the persimmon, is not found in the 

 county. 



19. Beaver dams are still found in a dilapidated condition along our streams, but 

 the animal has not been seen by any of the white settlers. 



20. Muskrats are not numerous, but it is thought they have increased in number 

 since the settlement of the county in 1805. 



21. The hare is common, and does considerable mischief to our nurseries and 

 young orchards, by gnawing the bark off the trees during winter. 



22. One of these little animals was found in its large nest lined with rabbit's 

 fur, on the outside of the wall of a well thirty feet below the surface of the earth ! 



23. The animal which 1 have designated Arvicola riparius, may be a different 

 species, perhaps a new one. It varies from the description given by Godman as 

 follows : the tail is not " nearly the length of the body," and is covered with short 

 brown hairs, except a few elongated ones at the tip, and these converge to a point; 

 on the closest inspection, but four teats were found, and these were situated be- 

 tween the hind legs, and were conspicuously large. Three young ones only were 

 obtained with the female which was brought to me. Its toes are fringed with 

 hairs which project over the nails. In other respects it accurately accords with the 

 characters of A. riparius. My specimens are about four inches long, from the tip 

 of the snout to the end of the tail ; the tail is eight tenths of an inch long. Its 

 minute eyes, short tail, and concealed ears, give this little animal a striking re- 

 semblance to the shrew. It is sometimes found in the woods, and sometimes un- 

 der stacks of corn left in the field. Two specimens, which I attempted to keep 

 in a box at different limes, gnawed wood like a moUse, ate corn, refused meat and 

 worms, were rather sluggish in their movements, and in a few days, without any 

 apparent cause, they died. They had received no injury in capturing them. One 

 was a male, the other a female. 



Godman says the upper molar teeth of the rat (Mus) " are very remarkable for 

 being inclined from before backwards." On looking over a considerable number 

 of skulls in my cabinet, I find the molar teeth of the above animal, and of the 

 Lepus Americanus, &c. quite as conspicuously inclined backwards as those of the 

 rat. 



