have two pectoral
mammae, and, rarely, additional ones upon the abdomen. Incisor
and molar teeth are always present, and, with one exception,
canines. The incisors are never more than two, nor are
there more than three premolars and three molars, on each
side, above and below.
Saving individual exceptions, which occur in one genus,
and may be regarded as abnormal, the hallux possesses a flat
nail. The hallux differs in form from the other digits of the
foot, and is so disposed as to be capable of more or less extensive
motion in adduction and abduction; and, very generally,
it is opposable to the other digits of the foot.
are divisible into- a.
, and c,