DAVID HEPBURN. [No. 3. 



different positions of the occipital condyles, and may exercise a 

 direct influence upon the size and shape of the condyles, yet I 

 think it can be shown that neither the attitude of the individual 

 nor the point of the skulTs balance upon the spinal column is 

 the determining reason or cause of the position assumed by the 

 condyles in relation to the glabello-occipital diameter of the skull. 



With this object in view I have examined the relation which 

 the position of the occipital condyles bears to the glabello- 

 occipital diameter of the skull in the different classes of crania 

 of several human races, as well as in Anthropoid Apes and in 

 some fætal and very young human crania. 



As a rule, craniologists are satisfied with the various abso- 

 lute measurements of a skull, and with calculating different 

 indices upon which to found a classification, but everyone has 

 observed how the same series of races do not always occur in 

 the same order under the different indices, and how very dis- 

 similar races may appear side by side under one or other of the 

 well-known subdivisions of the cephalic index, viz. dolichocephalic, 

 mesocephalic and brachycephalic. On this account, I have for 

 some time given attention to the proportions presented by the 

 principal cranial diameters in relation to definite and easily 

 accessible points upon the surface of the skull, in order to 

 ascertain vvhether savage and civilised skulls occurring under 

 similar cephalic indices were constructed upon similar proportions. 

 One of the points which I have carefully noted has given occa- 

 sion for the present communication. 



The position occupied by the occipital condyles in relation 

 to the glabello-occipital diameter of the skull can be readily 

 determined by using the segmenting callipers which I designed, 

 and whose description appeared in the Proceedings of the Royal 

 Society of Edinburgh, Volume XXII, pp. 601—618. The part 

 of the condyle from which the segmentation is effected is its 

 well-defined anterior margin; and in the majority of cases this 

 point will be found to correspond to the Basion. 



The terms "præcondyloid segment" and "postcondyloid 

 segment" express the amounts of the glabello-occipital diameter 



