Craniological Notes 349 



TIk'Ii \V(! lind : 



M,- 



It will 1)0 scon tliat fi-oiii tlie internuMal staii(I|i()iiit tho ce[ihalic broadth is raore olosoly 

 related to the l>izyi;(miatic- breadtli tlian eitlier of tliiwc to tlio miniiimiii frontal breadth. Thiis 

 a roconstnu.-tiou for .-i raco of tlio bizygoiiiatio broadth would l)e botter madc froiii the cephalic 

 than from tho frontal broadth. Thero can bo no ilonbt that wo Iiave in Bongal a ver-y groat 

 niixtiire of races, though it may be open to donlit wliothoi- it is sntfu-iontly wide to admit of oiir 

 sujjposing tho abovo corrolation coofEcionts to be olose onougli to be truo interracial values. 

 In partionlar a inaxiniuiu breadth of the living liead of 140'5 conld hardly Cf)rrespond to a 

 maximvun skull breadth of niore than 130 to 132 inni. Bat such a skidl broadth would be 

 extrenioly srnall for Kuropean raccs, whero, for exaiuplo, wo have : Bavarians 150-5, Whitochapel 

 English 140-0, French 145-2, and Hungarians 142-7. Tho aliove valuo.s ruust therefore be looked 

 upon as inerely provi.sional and suggo.sti vo. 



Now lot US compare theso values witli thoso withiii a singU; tribe. Tako tirst tho üraon 

 tribe of Chota Nagpur. We have : 



J/,, = 139-3I, J/,-=l()]-07, J/^ = 13il-4G, 

 (T,, = 4-5093, o-,. =3-216(), 0-2=3-8273, 

 ,•„= -5543, )-2,.= -4093, »■,,,.= -5807. 



Now in tho oaso of skulls tho frontal broadth is the character whioh is usually preserved 

 louger than the bizygomatie or cophalii.- brcadths, we will thcreforo write down the regression 

 equatious for the lattor breadths. 



Interracial Regression ßquations. 



(i) P^= 75-901 +-55005/'. 



(ii) P^= 54-790 + -2042 1 /•'+ -35892 C. 



(iii) P,.= 58-909 + -79805 F. 



(iv) P,.= - 7-249 + -31802 F+ -87174 Z. 



Ilere P^ and /',. are tho probable bizygomatic and cephalio brcadths of a race as deducod 

 from their known niean frontal breadth.s, or the conibination of these and their cephalic or 

 bizygomatic breadths respcctively. Applying these equations to i)rediot the mean bizygomatic 

 and frontal brcadths of tho Oraon tribe wc have : 



From (i) 7'^= 132-1, obsorved 130-5, 



(ii) 7'^= 131-7, „ 130-.5, 



(iii) /',, = 140-4, „ 139-3, 



(iv) /',.= 138-9, „ 139-3. 



We See at once that tho mean bizygomatic and cephalic breadths of the tribe are given fairly 

 closely by the interracial regression formidae. But how would these foi-midae ajiply to widely 

 difterent data ? Nut having measin-ements on the living head available, let us tako cranial 

 measurements, allowiiig 8 mm. for the flesh on all three breadths. This is probabh- too much 

 for the fi-ontal breadth and possibly too little for the cephalic breadth, but it will serve ow 

 purposes of testing the formulao. 



