'204 Dr. Gapper on the Mammalia of Upper Canada. 



Jlrvicola Gapperi.\ 



Meadow Mouse, with a tail more than half the length of the body ; short 

 rounded ears ; the back and upper part of the head chestnut ; sides and face 

 yellowish brown ; belly yellowish white ; chin and throat ash-coloured. 



Tab. IX. 



This Mouse is common on the steep banks of streams in the woods, 

 burrowing like the former ; it is very-fond of meat, and annoys the trapper 

 by eating the baits set for the Marten, and by throwing the traps. 



It is about 4 inches long from the tip of the nose to the insertion of 

 the tail ; the tail itself 1| inch. The head is moderately large, and the 

 nose on a line with the teeth : certainly it is not sharp-nosed like Dr. 

 Richardson's ./^ri?. JVovcboracensiSy the only species which at all agrees 

 with it ; the feet are whitish. I have caught several, all agreeing in colour, 

 size, &C.J 



Mus decumanus (Linn.)* The Brown Rat. 



Introduced. Only found in the warehouses near Lake Ontario. 



Mus Musculus (Linn.)* The common Mouse. 



Introduced. Very common all over the country. A great many are 

 frozen to death in the barns, where the native mice live in perfect security. 



Cricetus myoides (nobis.) Mouse-like Hamster. 



Hamster with a tail longer than the body ; large eyes and ears ; upper 

 half of the body mixed black and light reddish or yellowish brown ; 

 lower half pure white. 



Tab. X. 



Dental formula, incisors f, canines f, cheek-teeth f|. The cheek- 

 teeth have long roots, and are crowned with several little blunt tubercles 

 and convoluted ridges of enamel. It measures 3f inches from the tip of 

 the nose to the insertion of the tail ; the tail itself 3 j inches. The nose 



f Dr. Gapper having left this new species unnamed, we take the opportu- 

 nity of designating It by the name of the discoverer. — Ed. 



J Dr. Richardson to whom Dr. Gapper's MS. has beett communicated, 

 remarks, " this Arvicola diiFers from my Arv. Noveboracensis, in having more 

 " conspicuous ears, and is probably the animal Rafinesque named Novebora- 

 " censis ; but as his description is insufficient for correct discrimination, a new 

 " name had better be given to Dr. Gapper's animal. — J. R." 



