145 
‘ Adult specimens recently captured and placed together often kill and devour each 
other, mothers even eating their young. ) 
. “One evening I placed in a large cage two old males taken in different burrows. In 
the course of the night much fighting and crying was heard, and the next morning one 
was found to have been killed and partly devoured by his companion. The other was 
supplied with corn and fresh beef, both of which he ate; and in the course of the fore- 
noon a half grown house mouse was placed alivein the cage. This, without provocation, 
he at once attacked, asif in great rage, uttering his usual cry of anger, with his hair 
erected and bristling. In fighting he sprung upon the mouse, striking with his fore- 
feet, at the same time snapping quickly with his teeth, and then springing nimbly back. 
Finally he seized the mouse by the rump with his incisors, and thus broke his back bone. 
ter this the Jatter, which had fought as well as he could, ceased to resist, when the | 
meadow mouse, catching him in his teeth, threw him forcibly to some distance, and con- 
tinued to strike, bite and toss him about until he was dead. His anger then appeared 
to subside as quickly as it had risen, and in a few minutes he was observed placidly 
eating corn. The old males were always very pugnacious, biting and striking at any 
thing thrust at them. 
‘‘When much teased in this way, they sometimes turned on their backs, snapping 
with their teeth and striking with all their feet. 
‘‘ When enraged they uttered a low, harsh, creaking note, resembling very much that 
of a young puppy. If hurt, their voices were clearer and sharper. Sometimes they 
chattered their teeth in anger. The females were not so pugnacious, and were more 
silent; seldom crying out in anger, or fighting when teased. They were equally as car- 
nivorous, however, as the males. 
“Like mest Areicole, this species takes to the water boldly, and swims and dives 
readily.” : 
Sup-Genus Myonomes Rafinesque. 
< Arvicola of American writers. 
= Arvicola A, Hemectomys, Baird, M. N. A., 1857, 515 (type, A. réeparius, 
Ord. 
= Mynomes, Rafinesque, Am. Monthly Magazine, ii, 1817, 4. 
== Myonomes, Coues, Proc. Acad. Nat. Sci., Phila., 1874, 189. 
In Myoncmes the back upper molar has two external triangles and a 
posterior crescent. Middle upper molar with two internal triangles. 
Front lower molar with three internal and two or three external lateral 
triangles. Har unrimmed in front. Sole, 6-tuberculate. Fore claws not 
longer than hinder ones. Tail, about one-third the head and body, or 
more. Pelage, ordinary. Of maximum and medium size. 
ARVICOLA (MYoONoMES) RIPARIUS Ord. 
COMMON AMERICAN Mreapow MOUSE. 
1815. Arvicola pennsy'vanica, Ord, Guthrie’s Geog., 2d Am. ed., ii, 1815, 
292 (based on Wilson, |. c.)}—-Wagner, Suppl. Schreb., viii, 588.— 
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