34 PRIMITIVE TREPHINING IM PERU (ETH. ANN. 16 
eliminated. In a general way the operation would seem to have been 
similar to the later one in the anterior part of the head, though doubt- 
less performed several years earlier. As inthe later operation, traces of 
antecedent lesion are conspicuously absent, and the attendant features 
are hardly consistent with the supposition of considerable traumatic 
injury. 
The usual long-healed grooves over the temples appear in the speci- 
men, two of exceptional length on the right and two or three on the 
left; there are no other scars or abnormal features, save the vestigial 
preservation of the metopic suture. e 
CRANIUM 8 
(Plate XVI) 
Although fragmentary only, this specimen is well preserved, and 
represents a large and strong cranium, the bones averaging 5 mm, or 
more in thickness. The sagittal suture is almost completely anchylosed, 
and the lambdoid greatly obscured, indicating fully mature age. The 
specimen displays a well-defined artificial aperture in addition to a 
smaller opening, possibly artificial but more probably a pathologically 
persistent parietal foramen. 
The undoubted operation was located on the top of the head, i. e., 
near the antero-superior angle of the right parietal, centering 28 mm. 
from the sagittal suture and 35 mm. from the coronal. The aperture 
is approximately circular, averaging 30 mm. measured on the outer 
surface and 27 mm. on the inner. The traces of primary instrumenta- 
tion are indistinct; yet they appear to indicate careful manipulation of 
a blunt single-point cutting and grinding tool, held vertically on one 
side and obliquely on the other and worked with a short reciprocal or 
sawing motion in curvilinear fashion, in such manner as to define the 
circular aperture. The conformation of the cutting suggests an atti- 
tude of operator and position similar to that suggested by cranium 7, 
save that the patient faced toward the operator’s left; the head was 
apparently rotated considerably as the cutting progressed, while the 
position of the tool, as held in the right hand, was somewhat oblique, 
undercutting slightly on the side of the aperture toward the operator’s 
left, and overcutting considerably on the other side. It would seem 
that the random scratches due to slipping of the tool, particularly on 
the posterior and inferior sides of the opening, were subsequently 
ground or rasped away by rubbing with a rough tool which left fine 
but irregular scratches in the outer table. A few aberrant cuts extend- 
ing some distance from the aperture remain; two of these, parallel to 
the sagittal suture, extend forward from the aperture, one for 15 mm. 
and the other for 22 mm. to the coronal suture, as shown in the repro- 
duction. Despite the persistence of these marks, the character of the 
margins of both inner and outer tables indicates that the patient sur- 
vived the operation, and that slow reparative changes, not however 
extending to material bony growth, supervened. 
