210 



LECTURE VIII. 



On examining the skulls in front, tlie orbits of the brown 

 Cebus appear larger and wider ; in the albifrons they are 

 rounder, smaller, and the margins thicker and more massive. 

 The maxillary region, specially around the nose, appears nar- 

 rower in the brown Cebus, and rather compressed behind the 

 projecting root of the canine tooth, which has a downward 

 direction ; whilst in the albifrons it is oblique, thicker, but less 

 long and sharp. The two characteristic grooves on the inner 

 side of the canine tooth are in the brown Cebus deeper than 

 in the other species. 



On viewing the base of the skull (see figs. 78, 79), it seems 

 in the albifrons on the whole broader, more massive, and better 

 developed in all its parts than in the brown Cebus, in which 

 the palate is longer and narrower, the front teeth more pro- 

 jecting, and the zygomatic arch more curved. No difference is 

 seen in the arrangement or form of the molar teeth, but the 

 petrous bones are more pi'ominent in the albifrons. 



TABLE OF MEASUKEMENTS OP THE CEBUS IN MILLIMETERS. 







Albifrons. 



Apella. 



1 



Longitudinal circumference from posterior mai-gin of 









occipital foramen magnnm to alveolar margin 



150 



148 



2 



From anterior margin of occipital foramen to nasal 









suture ...--- 



54 



52 



3 



Fi-om posterior brim of occipital foramen to alveolar 









margin ...--- 



72-5 



73 



4 



From anterior brim of occipital foramen to alveolar 









margin ..---. 



60-5 



60 



5 



From anterior brim of occipital foramen to basilar 









suture ..-..- 



15 



13 



6 



From anterior brim of occipital foramen to posterior 









margin of palate . . - - - 



31 



32 



7 



Length of palate . . . . - 



29 



28 



8 



Greatest length of skull from alveolar margin to 









occiput ...... 



90 



91-5 



9 



Length from nasal suture to occiput 



77 



74 



10 



Greatest breadth of a vertical plane through the 









centre of the occipital foramen - - . 



54 



51 



11 



Transverse diameter on the posterior margin of the 









zygomatic arch . . . . - 



51 



50 



12 



Transverse diameter on the lowest point of the tem- 









poral fossa ------ 



40 



41 



13 



Distance between the zygomatic arches 



62 



57 



14 



Distance between the inner margins of the external 









aviditories ------ 



31 



32 



15 



Breadth of palate ----- 



19 



18 



16. 



Greatest diameter passing between the eyes 



42 



44 



17 



Breadth of the septum . . - - 



5 



5 



18 



Height of nasal aperture . . - - 



17 



11 



