ANTHROPOIDEA 703 
According to recent researches the Chimpanzee and some of the 
other Simidw 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 vertebree 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 
Cebidew generally have thirteen; and the same number obtains in 
the Chimpanzee and Gorilla, while the Orang resembles Man in 
having but twelve. The lumbar vertebre show a range in number 
of from four to seven. In the Stmiide there are four or five of 
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Fic. 335,—Skeleton of the Black-handed Spider Monkey (Ateles geoffroyi). 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 <dAfeles. 
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 Siwiide and Man, its greatest 
absolute length occurring in the Gorilla, and the relative greatest 
length being found in Hylobates, The Simiide never have less than 
five, and may have six sacral vertebre ; 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 vertebra. 
Except in the Simiide and JMacacus inuus, the number of caudal 
vertebree in the Apes always exceeds four, but they may be 
