150 
It is said to be very prolific, bringing forth three or four litters during 
the summer, and, according to Audubon and Bachman, sometimes as 
many aS nine young have been found in one nest. They furnish an 
important article of diet for the smaller carnivorous quadrupeds and 
owls. 
Two Ohio specimens of this Mouse are in the museum of the Smith- 
sonian Institution, one (young, No. 978) collected by Robert Kennicott. 
I am ignorant of the exact locality where they were taken. _ 
—Another Genus of thissub family, Synaptomys, represented by a single 
known species, S. coopert, will probably be found to occur in Ohio, as it 
has been discovered in an adjacent county (Franklin) of Indiana. 
tt has the general appearance of an Arvicola, but the dental characters 
differ, especially the incisor teeth, which have a longitudinal groove 
near their outer edge. 
GENus Freer Cuvier. 
Etymology: Latin—a Beaver. 
1766. < Castor, Linn., Syst. Nat., i, 1766, 78. 
1788. < Mus, Gm., Syst. Nat., i, 1788, 125. 
1792. > Myocastor, Kerr, “L. S. N., 1792 Gype Myopotamus coypus).” 
1800. == ber, Cuv., Legons, 1, 1800 (type Castor zibethicus). 
1829. < Lemmus, Fischer, Syn, 1829, 289. 
1827. == Ondatra, “ Lacepede.”—Less., Man., 1827, 286 (type, Castor zibetht- 
cus. 
Generte Characters.—Largest of the family. Form arvicoline, but tail 
nearly as long as body without head, compressed, nearly naked, reticulate. 
Hind feet set obliquely; soles naked, quadri-tuberculate; tees incom- 
pictely webbed. Fore arm bristle fringed. Muffle hairy, except the 
nasal pads. Hars small, with prominent angular antitragus. Whiskers 
short. Pelage lanuginous, beset with numerous long, glossy hairs. — 
Mamme, six. Perineal glands highly developed. Dentition and skull 
strictly arvicoline. Angular process of squamosal bone overhanging 
orbit behind; jugal, a mere splint, the squamosal and maxillary spurs 
actually in contact. 
FIBER ZIBETHICUS (L.) Cuvier. 
MUSKRAT. 
1766. » Castor zibethicus, Linn., Syst. Nat., i, 1766, 79, No. 3 (quotes Bris- 
son, Kalm, Sarrazin).—Erxl., Syst. Reg. Anim., i, 1777, 444, No.. 
2.—Bodd., Elench. Anim., i, 1784, 166. 
