CHAP. IV] THE GENERAL ANATOMY OF THE LEMUROIDEA 75 



tooth of that name when the jaw is closed. (This view is not 

 universally adopted : see Forsyth Major, Geological Magazine, 

 1900.) There are three premolar and three molar teeth; of the 

 latter, those in the upper jaw bear usually three cusps (though 

 two subsidiary cusps are often developed from the cingulum), 

 and consequently suggest the tri-tubercular type. (For fuller 

 details, cf. Chapter VI.) 



Vertebral Column. The vertebrae usually number fifty-six, 

 viz. cervical 7, thoracic 12, lumbar 7, sacral 3, caudal 27. The 

 spinous process of the second cervical vertebra is very large ; it 

 quite overshadows the other cervical spines, and offers some 

 resemblance to the corresponding part in the Dog. 



Other resemblances to the same type of mammal may be 

 observed in the thoracic region, where the tenth vertebra of 

 that series is " anticlinal " (as in some Dogs) ; in the lumbar 

 region, viz. in the number of vertebrae (7); in the presence of 

 " anapophyses " (found also in the Cercopithecidae) ; and lastly in 

 the curvature of the vertebral column as a whole. Such features 

 may be termed " primitive " ; probably they own a direct relation 

 to the quadrupedal mode of locomotion: judging from the highest 

 Apes and Man, they seem to be incompatible with the complete 

 attainment of the erect attitude. 



The sternum is rod-like, consisting of five large " sternebrae " 

 in series, and one small ossified element between these and the 

 elongated metasternal portion : eight rib-cartilages articulate with 

 the sternum on each side. 



The clavicle is relatively large and indicates the characteristic 

 freedom of the upper limbs. The scapula is obliquely elongated 

 and its coracoid process is slender, but falciform. 



The humerus has a straight shaft, the outer lip of the 

 bicipital groove being very prominent (probably the deltoid 

 eminence is fused with it), while the inner lip is absent. At 

 the lower end of the bone, the lateral supracondylar ridge is very 

 prominent, the radial and coronoid fossae are clearly demarcated 

 (as in Man) and an entepicondylar foramen is present. 



The olecranon process of the ulna is relatively slender : at 

 the lower end of the same bone, there appears to be an ossicle 



