ke third
in form; last lower molar double; cutting edge of first upper incisor
straight; mental foramen of mandible situated under first lower
cheek-tooth. Females average larger than males in all members of this
family. (See Orr, 1940:20.) The reverse is true in most other families
of mammals.

Hare is a name applied to any lagomorph whose young are born fully
haired, with the eyes open, and able to run about a few minutes after
birth. The young are born in the open, not in a nest. All of the species
of the genus _Lepus_ are hares. The species of leporids of all genera
other than _Lepus_, in North America at least, are rabbits. Their young
are born naked, blind, and helpless, in a nest especially built for them
and lined with fur. Considering the degree of development of the young
at birth, the gestation periods are about what a person would expect: 26
to 30 days in _Sylvilagus_ and 36 to 47 days in _Lepus_ (see Severaid,
1950:356-357). Vernacular names are misleading because the names jack
rabbit and snowshoe rabbit are applied to hares; also, Belgian hare is a
name applied to a rabbit (genus _Oryctolagus_) that is commonly bred in
captivity. There are many domestic strains and varieties of
_Oryctolagus_ and the animals are second only to poultry in some areas
as a protein food for man. Also, the pelts are sold as a source of felt
and many of the skins are dyed and processed for making fur coats and
other fur-pieces that appear on the market under names not readily
associated with rabbit.

Rabbits and hares are crepuscular and possibly more nocturnal than
diurnal. So far as I know they do not store food as do their diurnal
relatives, the pikas. Some leporids, however, have an unusual, and
possibly unique, method of processing food: Two types of vegetable
pellets are expelled from the anal opening of the digestive tract; the
dark brownish pellets, from which the nutriments have been extracted,
are feces, but the greenish pellets seem to be only slightly predigested
foods which are re-eaten. Southern (1942:553), among others, has written
about this. This system functionally resembles that in the ruminants
where a cud of vegetation is returned to the mouth, from one part of the
stomach, to be re-chewed and finally swallowed.

Because the causative organism of a disease that decimates dense
populations of small mammals, and some other kinds of vertebrates, was
isolated first in leporids, this disease, tularemia, is mor