38 PRIMITIVE TREPHINING IN PERU [ELH. ANN. 16 
There is nothing clearly to indicate how the smallest aperture was 
produced, though it has every appearance of artificial origin, and there 
are decisive indications, in the preservation of the tool marks and the 
retention of normal character by the diploe, that both of the medial 
openings are much more recent than the large one; indeed, it is doubtful 
whether the sufferer survived the later operation, and the conformation 
of the smallest aperture indicates pretty clearly that the underlying 
tissues were invaded so seriously as to produce death. In general, the 
operations display some evidence of both rectilinear and curvilinear 
incisions, such as those characteristic of the earlier members of the 
series, with definite indications of subsequent scraping or grinding. 
There is no definite indication of antecedent lesion; although the 
general appearance of the bone and the distribution of the openings 
vaguely suggest a diseased, possibly leprous or syphilitic, condition, the 
suggestion vanishes when the firm, sound bone is examined closely. 
Near the antero-inferior angle of the right parietal there is a darkened 
and evidently abnormal tract, more conspicuous in plate xxtv than in 
the specimen, perhaps the trace of local ostitis induced by a blow; 
there is also a dent, with some crushing of the bone, 35 mm. above 
the left orbit, and one of the customary vertical grooves appears over 
the right temple. 
CRANIUM 13 
(Plate XX V) 
This specimen is perhaps the least satisfactory of the series, chiefly 
because of the weathering and erosion to which it has been subjected. 
It is small but thick, averaging probably 6 or 7 mm., with the usual 
prominent occiput and attachments. The teeth are fairly developed 
and anchylosis is well advanced, indicating maturity; as usual, there 
are several small interparietals. 
The more significant of the two operations displayed by the specimen 
was performed in the top of the head, involving the sagittal suture, 
and apparently extending also into or across the coronal, though this 
is rendered somewhat doubtful by weathering and a recent fracture. 
This aperture is oblong, 12 mm. wide and (probably) 20 mm. or more 
long. No trace of instrumentation remains; the margins are thor- 
oughly rounded and the diploe is completely obliterated, giving an air 
of antiquity to the opening; undoubtedly the sufferer survived the 
operation for many years, despite the infraction of a modern rule 
against trephining over sutures. 
The locus of the second operation was the upper part of the left 
parietal, centering about 40 mm. from the earlier one, and about the 
same distance from the sagittal and coronal sutures. The aperture is 
oval, about 17 mm. in breadth by 22 in length. The surrounding bone 
is somewhat eroded, yet enough of the original surface remains to 
indicate clearly a reparative rounding by physiologic process, similar 
