734 



The following, to No. 4746 inclusive, are parts of the same skeleton of the Black-faced Drill 

 (Papio porcarius) : 



Hunter ian. 

 4723. The cranium. 



There is a slight paroccipital prominence ; that of the mastoid is rather more developed. 

 The jugular fossa is distinct from the precondyloid and carotid foramina. There is a rudi- 

 mental vaginal process outside the latter. The petrosal bifurcates anteriorly into an eustachian 

 and an apical process ; the latter underlaps the base of the pterygoid process, and the inner 

 surface of the petrosal is closely applied to the basisphenoid and basioccipital as far as the 

 foramen jugulare. There is, therefore, no ' foramen lacerum basis crauii.' The superoccipital 

 surface is almost flat, and slopes from the great foramen upwards and backwards, forming an 

 acute angle with the parietal surface, although the present cranium is not only of a mature 

 but of an aged individual. The temporal ridges are separated by nearly an inch at the occi- 

 pital ridge, where they most approximate each other : the sagittal and coronal sutures are re- 

 tained in the intermediate tract of the calvarium. The squamosal is perforated near its middle 

 by one or two small venous foramina, but there are no postglenoid outlets of the lateral 

 sinuses. The foramen ovale opens externally between the petrosal and alisphenoid, and the 

 nerve which it transmits afterwards pierces the base of the broad and backwardly extended 

 ectopterygoid : the entopterygoid plate is comparatively small, but ends in a hamular process. 

 The glenoid articular surface projects from the under part of the base of the zygoma and is 

 slightly convex : it is defended by a postglenoid process. The vomer divides the posterior 

 nostrils, and there is a venous sinus or foramen between its base and the presphenoid. The 

 facial part of the skull of this bestial quadrumane repeats the general characteristics of that 

 of the Papio Mormon, but the coalesced nasals are more prominent, and gradually expand as 

 they advance forwards : they unite with a smaller proportion of the premaxillaries. The 

 fossae between the nasals and maxillary tuberosities are shorter and wider, and the tuberosities 

 themselves are much shorter in proportion to their breadth, and are likewise more rugose. 

 The canines are relatively less, and their anterior groove is deeper. The anterior fang of the 

 first premolar of the upper jaw is less oblique and less developed than in the Papio Mormon. 

 The under jaw, like the maxillary part of the skull, is smaller than in the Papio Mormon. 

 There is a tubercle at the base of the fissure between the two principal external lobes of the 

 second and third lower molars. The pterygoid fossee are larger and deeper in the Papio 

 Mormon, and the third division of the trigeminal nerve grooves the base of the left ecto- 

 pterygoid, and does not so directly perforate that of the right as it does in the Papio porca- 

 rius. There is no postvomerine foramen in the Papio Mormon compared. The alisphenoid 

 joins the frontal, and is separated by the squamosal from the parietal. The calvarium is 

 detached, showing the two tables and diploe of the skull, except at the superoccipital where 

 the diploe is obliterated. The upper angle of the mastoid may be observed wedged in be- 

 tween the superoccipital and parietal. The limits of the interparietal may be traced upon 

 the inner surface of the calvarium. There is a shallow cerebellar fossa above the meatus 

 internus : the cochlear lamella extends nearer to the commencement of this meatus than in 

 the Chimpanzee. The foramen ovale is between the alisphenoid and the petrosal. The 



