206 CASTORID&. 
RODENTIA. CASTORID&. 
b \ aT 
a . / 
a ‘ ‘\ it 
a,c, Nat. size. Kent’s Hole. 
ARVICOLA AGRESTIS. Field Vole. 
Young Water-rat, Buck.anp, Reliquie Diluyiane, p. 265, pl. 
ratty Ills (2) 
Petit Campagnol des Cavernes, Cuvier, Ossem. Fossils, v. pl. 1, p. 54: 
Tue best preserved fossil specimens, from the caves at 
Kirkdale and Torquay, of the jaws and teeth of the species 
of Arvicola which are inferior in size to the common 
Water-rat, appear to me to be identical with the corres- 
ponding parts of two of our existing Voles. The Jaw a, 
and leg-bone c, figured above, agree with those of the 
species with rootless molars figured by Mr. Bell in his 
British Quadrupeds, p. 325, as the Field-vole, Arvicola 
agrestis of Fleming, which is the M/us arvalis of Pallas. 
Cuvier cites the jaws, teeth, and a thigh-bone, appa- 
rently of this little Rodent, from the cave at Kirkdale, 
which parts, he says, do not surpass in size the common 
Field-vole, (us arvalis, Linn.); but adds that the femur, 
though of the same length, is sensibly thicker, (plus large 
transversalement). The anchylosed tibia (¢) and fibula (/), 
fig. 77, from Kent’s Hole agree, like the jaws, with that 
of the existing Field-vole. A magnified view of the grind- 
