animal was playing about in the open part of its
cage, a large blue fly happened to buzz against
the wires. The little creature, although at twice
or thrice the distance of her own length from it,
sprang along the wires with the greatest agility,
and would certainly have seized it, had the space
between the wires been sufficiently wide to have
admitted her teeth or paws to reach it. I was
surprised at this occurrence, as I had been led to
believe that the Harvest Mouse was merely a
granivorous animal. I caught the fly, and made
it buzz in my fingers against the wires. ‘The
Mouse, though usually shy and timid, immediately came out of her hiding-place, and running
to the spot, seized and devoured it. From this
time, I fed her with insects, whenever I could get
them; and she always preferred them to every
other kind of food that I offered her.”
Family III. Castoridæ.
(Beavers.)
The animals of this family have a mouse-like form, and in many respects resemble the Muride in manners. Like them, too, they have perfect clavicles ; but they differ in the structure of their molar teeth, which are compound: their crowns presenting a flattened surface, on which the lines of enamel are so disposed as to form three folds on the outer side, and one on the inner, in those of the upper jaw; while those of the lower. have this arrangement reversed. ‘The incisors are very strong, and chisel-shaped. The muzzle is short and rounded ; the ears short, the hind feet robust ;
