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CHAP. XVII.] MAMMALIA. I75
completely covered with hair, although prehensile, and therefore
not so perfect a grasping organ.
Sub-family, Mycetinas, consists of but a single genus, 3fycetcs
(10 sp.), the howling monkeys, characterized by having a hollow
bony vessel in the throat formed by an enlargement of the hyoid
bone, which enables them to produce a wonderful howling
noise. They are large, heavy animals, with a powerful and
perfect prehensile tail. They range from East Guatemala to
Paraguay. (Plate XIV., vol. ii., p. 24.)
Sub-family, Pitheciinse, the sakis, have a non-prehensile
bushy tail. Pithecia (7 sp.), has the taU of moderate length
while Brachiurus (5 sp.) has it very short. Both appear to be
restricted to the great equatorial forests of South America.
Sub-family, Nyctipithecinse, are small and elegant monkeys,
with long, hairy, non-prehensile tails. Nyctipithecus (5 sp.), the
night-monkeys or douroucoulis, have large eyes, nocturnal
habits, and are somewhat lemurine in their appearance. They
range from Nicaragua to the Amazon and eastern Peru. Saimiris
or Chrysothrix (3 sp.), the squirrel-monkeys, are beautiful and
active little creatures, found in most of the tropical forests from
Costa Pica to Brazil and Bolivia. Callithrix (11 sp.), are somewhat
intermediate between the last two genera, and are found
all over South America from Panama to the southern limits of
the great forests.
Neotropical
8t;b-regions.
Family 5.—HAPALID^. (2 Genera, 32 Species.)
General Distribution.
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