The occipital bone in Primates 



by 

 Prof. R. J. Anderson (Galway). 



(With 14 Fig.) 



The measurements of tlie occipital bone in Primates are given 

 below as follows, the shortest distance between the anterior superior 

 spine and the anterior part of the basilar part, the distance from 

 angle to angle (at the widest part of the occipital, generali}^ where 

 the angles were not very well defined), the anteroposterior diameter 

 of the foramen occipitale, the basilar process, the distance from the 

 posterior margin of the foramen to a prominent point near the apex 

 called protuberance for convenience. Lines are also referred to, these 

 do not correspond to those in man necessarilj^ Then the condyles are 

 given and some other interesting points. It is obvious from the mea- 

 surements that differences due to age are important in estimating 

 differential characters. Inspection shows that the tabular part which 

 gives the relief of the brain prominences beneath, in the young, may 

 become less convex at the sides and even somewhat depressed at one 

 side of the median ridge in the old. 



The grooves (for the mesial cerebellar part) in a young Hylobates 

 leuciscus, and a young Semnopithecus entellus, with the corresponding 

 mesial prominences externally, contrast with the fossa above the 

 foramen magnum in Hylobates agilis of a late adult age. Where, 

 however, the heads become muscular and large, the muscular ridges, 

 crests &c., may deprive the skull of much of its early character. So 



