188 



MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 



In the first place we will consider the true epactal bone, or os Incfr. It exists in all races; it 

 becomes a characteristic of the Peruvian or Inca race only by reason of its great frequency among 

 them. How often it is found in them more than among other peoples hitherto studied will be seen 

 in the accompanying table (Table A). 



Flo. 31 Inca bono (No. H. 13). 



FIG. 32 Inca bone (No. H. 29). 



Figs. 31 and 32 represent typical forms of this bone in two varieties described by Virchow.* 

 In one the persistent transverse occipital suture runs directly from one asterion to the other, and 

 seems but a continuation of the parieto-mastoid suture. In the other the ends of the transverse 



FIQ. 33 Incomplete Inca bone (No. H. 14). Flo. 34. Quadrate hono (No. H. 48). 



suture join the lambdoidal on each side, a short distance above the asterion. The epactal bone 

 shown in Fig. 31 was complicated with a multitude of Wonnian bones, many of which, very 

 minute, pertained to the outer table only, and, falling out, left the broad, indefinite border shown 



t Zeitechrift fur Ethnologie, 1888, p. 470. 



