MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



In the first iilace we will consider the true ei>actal bone, or os Incce. 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). 



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 parietomastoid suture. In the other the ends of the transverse 



Fia. 33— Incomplete 



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 Wormian bones, many of which, very 

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



t Zeitschrift fur Etlmologie, 1888, p. 470. 



