36 PRIMITIVE TREPHINING IN PERU (ETH. ANN. 16 
anchylosed and partly obliterated and others distinct, while the teeth 
are fairly developed, except that one posterior molar is lacking and the 
other imperfect, the features collectively indicating middle age. 
The operation displayed by this specimen is in the posterior angle of 
the right parietal, extending to both sagittal and lambdoid sutures. 
The aperture is rudely cireular and 28 or 29 mm.in mean diameter. 
Although the bone is in excellent preservation, it is impossible to deter- 
mine the manner in which the operation was performed, since all definite 
traces of instrumentation have been obliterated by reparative process, 
including the complete replacement of the diploe and the development 
of strong spicules of new bone pushing into the aperture. The most 
conspicuous of these spicules is that clearly shown in both reproductions 
at the lower side of the opening. The sharp angle immediately above 
also represents well-developed bony growth. While the record of the 
operation is thus obscure, it is nevertheless fairly if not finally evident 
that the operator proceeded in a manner unlike that represented in 
most or all of the preceding specimens. The conspicuous feature of the 
artificial work lies in the fact that the bone attenuates uniformly toward 
the edges of the aperture as if removed by scraping or grinding, perhaps 
with an edge or rasp-like side of considerable length. (This is well 
shown in plate xx.) There are, however, a few exploratory scratches, 
notably one extending forward from the upper margin of the grinding, 
30 mm. from and nearly parallel with the sagittal suture. 
No antecedent lesion can be detected, but it is certain that the patient 
survived the operation long, probably many years. The cranium dis- 
plays three great grooves over either temple arranged in symmetric 
pairs. 
CRANIUM 11 
(Plates XXI, XXII) 
Although somewhat bleached and weathered, this cranium is in excel- 
lent condition, The occiput is singularly flattened, particularly on the 
left, as shown imperfectly in the right aspect represented on plate XXII. 
There is some flattening also of the face, with an apparently abnormal 
shortening of the mandible. Two or three small interparietals oceur. 
The bones are rather thin, ranging from 24 to 44 mm. The teeth are 
exceptionally mature for the collection, though the sutures remain 
distinct. 
The operation for which the specimen is notable was performed near 
the center of the frontal bone, a little to the right of the median line, — 
and extending from 37 mm. above the orbit to within 22 mm. of the 
coronal suture. The aperture is an elongated ellipse, 21 or 22 mm. in 
maximum width by 40 in length, measured on the feather edge of the 
inner table. In this ease, too, all definite traces of instrumentation are 
lost, partly by weathering though chiefly by reparative process. The 
margins of both tables are rounded, the diploe is completely obliterated, 
