ANTHROPOIDEA 



703 



According to recent researches the Chimpanzee and some of the 

 other Simiidce exhibit a more or less close approximation to the 

 sigmoid curvature of the vertebral column which is so characteristic 

 of Man, and there is also some approach to it in the Baboons. 

 The number of dorsal vertebrae in the Apes may vary from eleven, 

 as in some species of Cercopithecus and Macacus, to fourteen in 

 certain forms of Hylobates, and to fifteen in Nyctipithecus. The 

 Cebidce generally have thirteen ; and the same number obtains in 

 the Chimpanzee and Gorilla, while the Orang resembles Man in 

 having but twelve. The lumbar vertebrae show a range in number 

 of from four to seven. In the Simiidce there are four or five of 



FIG. 335. Skeleton of the Black-handed Spider Monkey (Ateles geo/royi). From De Blainville. 



these vertebrae, the length of the lumbar region being shorter in 

 this family than in the other Apes, with the exception of Ateles. 

 The shortness of the lumbar region in the last-named genus is 

 compensated by the relative length of the dorsal region, as is 

 shown in Fig. 335. 



The sacrum is longest in the Simiidce and Man, its greatest 

 absolute length occurring in the Gorilla, and the relative greatest 

 length being found in Hylobates. The Simiidce never have less than 

 five, and may have six sacral vertebrae ; while in the lower forms 

 there are generally only two or three, although occasionally four in 

 some of the American forms. The Orang and some of the Baboons 

 make the nearest approximation to Man in the marked angle 

 formed at the junction of the sacrum with the lumbar vertebrae. 

 Except in the Simiidce and Macacus inuus, the number of caudal 

 vertebrae in the Apes always exceeds four, but they may be 



