The Night-Monkeys are small and elegant animals covered with long hair, and
having long bushy tails, which are not prehensile, although they can be
curled round a branch of a tree. The caudal vertebræ in these creatures are
consequently not flattened from above downward, as is the case in the
prehensile-tailed groups, but rounded. Their lower incisor teeth are set
vertically and their thumb is fairly well developed.
This sub-family contains three genera, the Squirrel-Monkeys
(_Chrysothrix_); the Whaiapu-Sais, or Titis (_Callithrix_); and the typical
Night-Monkeys, or Douroucolis (_Nyctipithecus_).