INTRODUCTION. 167 



The maximum parietal width is, as stated above, given under 

 the head of ' Extreme Breadth ; ' the maximum occipital is taken 

 from the point ('asterion' of MM. Broca and Topinard) where the 

 occipital, parietal, and temporal bones of one side meet, to the cor- 

 responding* point on the other ; i. e. between the two most distant 

 points of the lambdoid suture. 



It is not unusual to give a number of ' indices ' stating the pro- 

 portions existing between various measures of length in addition 

 to that usually called the ' Cephalic Index,' which gives the rela- 

 tion of the breadth of the calvaria to the length taken as ioo. 

 Thus we have an index of the relation of the height to the length 

 and of the height to the breadth ; a f nasal index ; ' an ' orbital 

 index ; ' and a ' maxillary x index,' giving the relations of the basi- 

 cranial line to a line passing from the middle of the anterior 

 border of the foramen magnum, the ' basion ' of Broca, to the nasal 

 spine. The value of these measurements is beyond question ; but 

 as the important point in each of these cases is simply one of 

 greater or less magnitude, oscillating within narrow limits, the in- 

 convenience of additional statements of proportion is not counter- 

 balanced by much corresponding advantage. I have, however, 

 given one measurement of proportions in addition to the ' Cephalic 

 Index;' and this, which I have called the ' Antero-posterior Index,' 

 gives the relation which is held to the extreme length of the skull 

 by that part of the extreme length which lies anteriorly to the 

 auditory foramen. The extreme length being taken as above 

 described, it is divided into an anterior and a posterior segment 

 by a line passing as a tangent to the anterior border of the audi- 

 tory meatus, and prolonged so as to cut the line of extreme length 

 at right angles. The proportions between these segments may be 

 very readily obtained by fitting an indicator to one of the longer 

 sides of M. Broca's ' cadre a maxima 2 ? and, when the instrument 

 is so applied as to take the extreme length, adjusting the indi- 

 cator so as to ran as a tangent to the anterior edge of the auditory 

 meatus. The vertical line thus obtained falls always some way 

 behind the junction of the coronal and sagittal sutures ; but though 



1 Virchow, 'Archiv fur Anthropologic,' vol. iv. p. 63, 1870. 



2 For description of this useful instrument, see ■ Bulletin Soc. Anthrop. Paris,* 

 torn. iv. (2 de Serie), pp. 101-104, 1869 J or 'Memoires d' Anthropologic par Paul Broca,' 

 torn. i. p. 152, 1871. 



