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.] The 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 

 Simiidte 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 vertebrae, 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 Semnopithecus, 

 Cercopithecus , Colobus, Macacus, Cynocephalus, the distinguishing 

 characters of which have already been referred to (p. 9). 



All the Catarrhini, as the Old- World 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-World or Platyrrhine Monkeys. Their 

 dental formula is invariably I. f, C. \, Pm. , M. x 2 = 32. 



The American or Platyrrhine Monkeys consist of two families, 

 the first of which, the Cebida, has for its dental formula, 1. f , C. \, 

 Pm. J, M. f 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 laniger exhibited. 



