MEMOIRS OF TIIH NATIONAL ACADKMV OK SCI KNCKS. 1 S3 



each and every series, it is, of (Mnirsc, tlic type skull of tlic lot in rwvy icsitect, so (hi- as the 

 investigation lias jjone. 



I'.ut if, as must always he the case, no skull expresses the theoretical mean of every series of 

 indices, Ihcii we lake the skull which averajjes nearest the theoretical mean. Therefnre, of our 

 sujiposed lot of ;» skulls we select, let us say, from the lirst series of indices, .'{ — the skull 

 having an index most nearly expressing the mean of variation, the skull having an index next 

 greater than this, and the skull having' an index next smaller. Now, supposing that we have ten 

 series of indices, let us say that the skull which expresses the theoretical mean of tlu^ first series 

 eomes nowhere near il in any other si'ries, while the skull next liclow the theoretical mean in the 

 series of indices under consideration is the theoretical mean of two other series of indices, and 

 stands either just above or just below the mean in every series. The latter, tlieii, is very likely 

 the type sought. 



To state it more methodically : We have measured a h)t of skulls, have reckoned their indices, 

 and have arranged the several diderent kinds of indices in as many dillerent ordinations. In each 

 ordination we.seleet the index most nearly expressing the mean of variation and call it No. 1 ; the 

 index next above and index next below this we call No. 2. The index next above the greater No. 

 2, and the index next below the lesser No. 2 we call No. 3, and so on. Now let us add together, 

 for each skull separately, the Nos. 1, 2, .{, etc., expressing the jiosition of the several indices with 

 regard to the theoretical mean of radiation of each series of indices. Divide the sum thus obtained 

 by the number of series of indices. The skull whose indices thus treated give the lowest (luotient 

 is the tyiie. 



In the present case, however, it must be remembered that thcSaliido skulls are much Itroken, 

 so that only a few can yield a complete series of measurements. The type skull, therefore, mpart 

 owes its selection to its good preservation, it being represented in every .series of indices. It can 

 not be said to be the type of ."»7 skulls, perliaps, but in a general way, all things considered, 

 it is the best representative of the characteristic dimensional relations of crania of the people 

 in question. Its most aberrant feature consists in the unusal height of the orbits, shown by the 

 orbital index fltJ.Oo, while the theoretical mean of the orbital indices is !)().90. 



The tyiie .skull thus selected is II. 40; its five views are shown in plates 55 to 5!t, inclusive. 

 Of skulls in good condition U. 7 and U. 15 approach nearest to the type. 



<> 15. I'KOCESSES AT I5ASE OF SKULL. 



There is evidence, in the archiXiologic find of Los Mnertos and Las Acequias in the shapes of 

 the pottery, etc., that this people, like the modern I'ueblos, were accustomed to carry heavy 

 burdens on the head. Such being the case, we miglit reasonably expect to find the various proc- 

 es.ses for muscidar anil ligamentary attacliments at the baseoftiie skull strong and prominent; 

 but, on the contrary, we tind them unusually subdued and weak. It may be that our exjiecta- 

 tions are unlbunded; that the load on the head, once well balanced, required little muscular exer- 

 tion to sustain it. 



The Fnioit. — In 4(i adult skulls, with this process well preserved, compared with the live 

 forms of Broca,* we lind that 27 agree with his zero or lowest form, that 1!) resemble his No. 1, 

 and that none are to be considered of a higher grade than this. It has been conjectured that tiie 

 general pressure which has llattened the occiput in these skulls may have hindered the full 

 develojiment of the inioii; but the fact that all the processes of the base are weak, and that the 

 inion is ill developed in skulls where the pressure did not fall upon it, seems to indicate that pres 

 sure cau at most account for only a part of the subdued features of the inion in this series. 



S^ 16. THE PTEKION. 



Of the pteria :V2 are sufficiently preserved to be studied with profit. They occur in 2-1 skulls, 

 1.3 im the right side, 19 (m the left. Four exhibit the character iilainly, but can not be measured. 

 The reumining 28 (see Table xxv) are easily measured. Only 8 skulls have the pteria intact on 

 both sides. i 



"Bkoca: InstructioiiH crani()lo;;ifliiuH i-t craiii(>mctri<|iii-s. PI. vi. 



