130 THE GENERAL ANATOMY OF THE CERCOPITHECIDAE [SECT. A 



Vertebral Column. The cervical vertebrae are seven in number, 

 the thoracic and lumbar together are nineteen, of which twelve or 

 thirteen usually bear ribs, and are thus to be regarded as the true 

 thoracic elements. The tenth vertebra is often the anti-clinal 

 element. Three sacral vertebrae and a very variable number 

 (3 — 26) of caudal vertebrae complete the series. In the lumbar 

 region, spine-like anapophysial processes (Fig. 81) are directed 

 backwards from each vertebra to embrace the anterior zygapo- 

 physes of the succeeding one. 

 The curvature of the vertebral 

 column is much simpler than in 

 Man, being a simple thoraco- 

 lumbar curve whose concavity 

 is directed downwards. An- 

 terior to this is a cervical 

 curvature in the opposite 

 direction. Posteriorly, owing 

 to a tilting upwards of the 

 sacrum, an appearance of con- 

 vexity downwards is often 

 seen especially in the Baboons 

 (Cynocephali) (Fig. 82). 



The sternum consists of 

 six ossified segments, all of 

 which are rod-like, save the 

 presternal element. The costal cartilages of eight ribs reach the 

 sternum directly. 



The clavicle does not shew the degree of sinuosity of the 

 human bone. The sternal end is straight, the outer portion being 

 concave forwards. A strong deltoid ridge replaces the tubercle of 

 that name in the human clavicle. An impression for the M. sub- 

 clavius is distinct. 



The scapula is very broad (Fig. 83 a) (when measured in the 

 general direction of the spine) in comparison with its diameter 

 from the superior to the inferior angle: its "index" is 118 approxi- 

 mately. In Man, the index is about 65. The acromion process is 

 comparatively small. The scapula in general resembles those of 

 animals with quadrupedal gait rather than those of the Simiidae. 



Anapophyses 



Fig. 81. Four thoracic and three lumbar 

 vertebrae of a Cercopithecus monkey (Cerco- 

 pithecidae), with anapophyses projecting 

 laterally from the pedicles. 



