MEMOIllS OF THE NATIONAL ACADEMY OF SCIENCES. 185 



It is seen from these notes that the Peruvians offer no case of sagittal synostosis comparable 

 to that of the Suladoans. This is the conclusion arrived at by considering that all three of the 

 above skulls are at least mature and show a sagittal ridge. 



Yucatecs. The Yucatecs offer the following specimens of unique sagittal synostosis: 



No. 6i&amp;gt;6, a well-preserved skull without mandible; basilar suture closed; all permanent teeth 

 cut; second upper right premolar shed ante-mortem; teeth not worn; sagittal suture obliterated; 

 no other synostosis. 



No. 628, a well-preserved skull without mandible; basilar suture closed; all permanent teeth 

 cut; left upper third molar lost, probably ante-mortem; enamel of teeth not worn; sagittal suture 

 obliterated; a little commencing synostosis just above the lambda; no other synostosis. 



Clifr&amp;gt;tittnx. No. 1415, small, rather heavy and well-preserved; basilar suture closed; third 

 upper molars cut (lower jaw not found); right upper third molar lost; the teeth show wear sufli- 

 cient to slightly expose the dentine except in the case of the left upper third molar, of which the 

 enamel alone is worn; the sagittal is cob ssitied throughout its entire length on the inner table, 

 and all but its anterior fifth on the outer table; no other synostosis. 



No. 1430, medium size; facial bones separated from cranium and only right side of mandible 

 preserved; third molars cut; but all but right lower have been lost; basilar suture closed; the 

 enamel only of the teeth is worn; sagittal entirely obliterated; no other synostosis. 



No. 1507, small skull; right temporal and cerebellar regions broken away; mandible broken 

 across the symphysis; basilar suture closed; all third molars cut, but right upper one has been 

 lost; the second and third molars have their enamel only worn; some other teeth have their 

 dentine slightly worn. The sagittal is coossified entirely on the inner table and all but its most 

 anterior portion on the outer table; no other synostosis; lambdoid quite complicated. 



No. 1748, consists of the cranial vault, only, from a good-sized, rather scaphoid specimen; 

 sagittal completely obliterated on each table; coronal and lambdoid fully open; no way of judging 

 age. 



A skull which is less satisfactory to discuss, as all its teeth have dropped out post-mor 

 tem, is_ No. 80li, a well-preserved recent skull; basilar suture closed; third molars cut; all 

 teeth dropped, but there is no alveolar absorption. There has been a large ox epactale; it is now 

 (irmly coossified to the parietals, and they in turn to each other, the sutures being thoroughly 

 obliterated; other sutures, including that between the epactal and occipital, open. Bather a 

 scaphoid skull. 



In many of the Californian skulls there is a prominence, sometimes prolonged into a ridge, just 

 behind the bregma; none of the above synostotic skulls show this peculiarity except No, SOU, 

 which lias a slight ridge. In some skulls, however, where synostosis is more general and probably 

 a purely senile change, it is evident enough. 



Mound builders. No. 556, a mutilated skull of a Floridian without mandible; state of basilar 

 suture indeterminable; upper set of permanent teeth all cut; right upper third molar shed ante- 

 mortem, teeth all deeply worn; complete sagittal obliteration; no other synostosis. 



No. 1110, a mutilated skull of a Floridian without mandible; basilar suture closed; teeth 

 mostly shed ante-mortem and rear alveoli much absorbed; sagittal obliterated except at ils 

 anterior half centimeter; very slight commencing synostosis of lambdoid; no other syuostosis of 

 brain capsule. This is probably the skull of quite an old person. 



No. 730, a fairly well-preserved skull from Kentucky with mandible; basilar suture open; 

 all permanent teeth cut except third molars; no teeth shed ante-mortem; all teeth lost post 

 mortem except right upper first molar and both lower first molars; these teeth are not worn; 

 sagittal suture open anteriorly for its first 18 millimeters; behind this it is obliterated to within 

 16 millimeters of the lambda, and the space of these last 16 millimeters is partially co ossified; no 

 other synostosis. As far as age and a globose appearance are concerned, this skull is essentially 

 similar to the Saladoan, H. 17. 



No. 1012, a large, well preserved skull, with mandible, from Illinois; basilar suture closed ; all 

 permanent teeth cut; right upper molars, left upper lirst and third molars, and both lower lirst 

 molars shed ante-mortem and alveoli absorbed; teeth somewhat worn; complete sagittal oblitera- 



