INTRODUCTION. 165 



The ■ extreme length ' has been taken neither from the fronto- 

 nasal suture, as Professor Virchow takes it 1 , nor from the { gla- 

 bella ' strictly so called, i.e. from the interspace separating or 

 connecting 1 , as the case may be, the two supraciliary ridges, but 

 from a spot immediately above that area — just, in fact, where the 

 upper part of the frontal begins to rise into it. This appears to be 

 the most reasonable spot to take for an antero-posterior measure- 

 ment of the brain-case, as the applied arm of the compasses comes 

 there into nearer relations with the cavity containing the cerebrum 

 than at either of the two other points specified. The most posteriorly 

 placed part of the skull, whatever it may be short of an exagger- 

 atedly developed occipital spine, is the point to which the other 

 arm of the compasses is applied for this measurement. This point 

 will sometimes be found at the base and on the upper surface of 

 the external occipital ' spine,' or * protuberance,' or ' inion,' in cases 

 in which the superior occipital squama is flat and takes a perpen- 

 dicular direction : and here what may be called the ' fronto-inial ' 

 diameter is identical with the ( fronto-postremal ' or extreme length 

 of the skull. It is usually in bra chy cephalic skulls that this is 

 the case ; it is however by no means rare in the dolichocephalic 

 forms. Sometimes, as in the more typical dolichocephalic skulls, 

 the most posteriorly placed point of the skull is to be found upon 

 the superior squama occipitis, which in these cases is as markedly 

 convex as in the other class of cases it is markedly flat ; and here 

 a difference, which may amount to as much as half an inch, may 

 exist between the 'fronto-inial' and the extreme length. This differ- 

 ence has been considered to furnish a measure of ' occipital dolicho- 

 cephaly 2 / or of the extent to which the posterior cerebral lobes 

 overlap the cerebellum. It must be remarked, however, that in 

 some skulls, where we find the occipital spine taking the form 

 of a broad transversely running ridge, in which the lineae supremae 3 

 of Merkel are fused with the lineae superiores nuchae, the slightness 

 of the difference between the two cranial measurements in question 

 may cause us to under-estimate the extent of the cerebral overlap, 



1 ' Archiv fur Anthropologic/ vol. iv. p. 59, 1870. 



2 For ' Occipital dolichocephaly,' see Gratiolet, Bullet. Soc. Anth. Paris, ii. p. 254, 

 1861 ; Broca, ibid. iv. pp. 49-56, 1863, or his collected Memoires, ii. p. 27, 1864 ; 

 British Association Beport for 1875, p. 152. 



3 For explanation of these terms, see Dr. Fr. Merkel, ■ Die Linea nuchae suprema,' 

 1871. 



