CHAP. IV] THE GENERAL ANATOMY OF THE CERCOPITHECIDAE 129 



articulation. The malar bone in these apes may also be prolonged 

 backwards so as to touch the parietal bone. 



The palate is elongated, the glenoid fossa deeper than in the 

 Lemurs; the post-glenoid tubercle is well developed and spiny. 

 The tympanic bone is expanded to form a tube which protects 

 the external auditory meatus and tympanic membrane, and there 

 is no auditory bulla in the Old-World monkeys, though this feature 

 characterizes their New- World representatives. The anterior and 

 inferior part of the petrous portion of the temporal bone is 



Fronho-squamous 

 arh'cularion 



, Lacrymo-ethmoidal 

 arh'culah'on 



Fig. 80. Cranium, with mandible, of a Macaeus monkey (Cercopithecidae) ; 

 note the absence of an auditory bulla; the substitution of fronto-squamous and 

 fronto-maxillary for spheno-parietal and lachrymo-ethmoidal articulations : note also 

 the number of teeth, and compare with Figs. 18 and 21. 



commonly inflated in appearance. The basi-occipito-sphenoidal 

 suture persists for some considerable time after the completion of 

 the dentition. 



The dental formula is identical with that of Man (the New- 

 World monkeys having an additional premolar tooth in each 

 jaw); the molars commonly bear four distinct cusps arranged in 

 two pairs, an anterior and a posterior. (For fuller details, v. 

 Chapter VI.) 



I), m. 9 



