This family, like the preceding, has been constituted for the reception of
two animals which are so remarkably distinct from all the other species of
Lemurs, as to necessitate their being thus segregated. Between these two
forms however, so close a relationship exists, that they have often been
considered as only varieties of the same species. The family, therefore,
consists, as in the _Chiromyidæ_, of a single genus, the characters of
which constitute also those of the family.