70 
OSTEOLOGICAL GALLERY. 
the large size of their teeth, and, in common witli other Monkeys, 
the opposability of their halluces or great toes, a character which 
may be seen very clearly in the mounted skeleton. The family 
contains the Gorilla, Chimpanzee, Orang-Outang, and the Gibbons, 
of all of which skeletons and series of skulls are exhibited. The 
fine series of Chimpanzees^ skeletons in the upper part of Divs. C 
and D, and the Orang-Outang skulls collected by the late Rajah 
Brooke and others in Borneo, are especially worthy of notice. 
[Case 3.] ^^he Cercopithecidce, containing the rest of the Old-World Mon- 
keys, are of very various sizes and proportions, some having no 
tails at all, while others have enormously long ones, which are, 
however, never prehensile. They are distinguished from the 
Simiidce by the quadrupedal position of the body, and the conse- 
quent modification of their skeleton, especially the shortening of 
their fore limbs, which are always exceeded in length by the hind, 
by their lower central incisors being larger than the outer ones, 
the converse holding in Man and the Anthropoids, by their more 
numerous back vertebrje, and by many other less definite charac- 
ters which remove them further from Man towards the ordinary 
lower Mammals. Skeletons and skulls are exhibited, in Case 3, 
Divs. A-D, of specimens belonging to the genera Semnupithecus, 
Cercopithecus, Colubus, Macacus, Cynocephalus, the distinguishing 
characters of which have already been referred to (p. 9). 
All the Catarrhini, as the Old-M^orld Monkeys and Man are 
called, have an osteological character in common (besides the 
external points noted on p. 9), viz. the presence of a long bony 
tube or meatus, leading from the outer to the inner ear, which is 
entirely absent in the New-AVorld or Platyrrhine Monkeys. Their 
dental formula is invariably I. C. j-. Pm. M. x 2 = 32. 
The American or Platyrrhine Monkeys consist of two families, 
the first of which, the Cebidce, has for its dental formula, 1. C. ], 
Pm. g, M. I X 2 = 36, thus differing from the Catarrhini by having 
an additional premolar on each side of each jaw. Their external 
characters have already been referred to (p. 9)*. One of the 
genera of this family, Mycetes, the Howling Monkeys, is remark- 
able for possessing a bony enlargement of the hyoid or tongue- 
bone, in which the extraordinary howling or roaring sounds emitted 
by these Monkeys are produced ; this structure may be seen in situ 
in the skeletons of Mycetes laniyer exhibited. 
