(iTJADE,UPEDS OE NORTH AMERICA. 
GENUS LUTRA. — Ray., Cuv., Mustela spec., Linn., Aonyx, Lesson. 
DENTAL FOEMULA. 
6 1—1 5—5 
Incisive Canine— ■, Molar — =86 
0 i ^ 5 
i HE second inferior incisor on each side, a little receding in most of the 
species ; the canine much dilated, hooked ; first superior molar, small, 
blunt, and sometimes deciduous ; the second, cutting ; the third, of similar 
form, but larger; the fourth, with two external points, but furnished with 
a strong spur on the inner side ; the fifth has externally three small points, 
with a broad spur internally. The inferior molars in this genus vary 
from five to six, the first being Avanting in some of the species. 
Head large and flattish, terminating in a blunt muzzle ; ears short and 
round ; tongue slightly papillous. Body long and slender ; legs short ; 
toes five on each foot. In some of the species the fifth toe on the hind 
foot is rudimental. Toes webbed, armed with short claws which are not 
retractile. Tail, not as long as the body, thick, and flattened hori- 
zontally. 
Body covered externally with long, rigid and glossy hair, with a softer, 
shorter, downy fur intermixed. 
On each side of the anus, there is a small gland secreting fetid matter. 
All the species are good swimmers, live along the banks of rivers and 
ponds, and feed on fish. 
The generic appellation is derived from Lutra — an Otter : from the 
Greek Aouai (lous), wash. 
There are eleven species enumerated by authors, inhabiting the follow- 
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