MEMOIUS OF TUE NATIONAL ACADEMY OF SCIENCES. 185 



It is scon fniin those nolos that the Poniviaiis oflor no case of sagittal synostosis ooniparablo 

 to tliat oftho Saladoans. This is tlu^ conilnsion arrived at by cousideiiuj^ that all tliroo of the 

 above skulls are at least matiiie and show a sagittal ridfje. 



YiiciiliTs. — Tlie Yucatecs olVer (he lollowint; siioc^iineus of unique sagittal synostosis: 



No. (>:.•(), a well i)reseived skull without mandible; basilar suture elosed; all ]ternianont teeth 

 cut; second uiip(>r right premolar shod autemortcm; teeth not worn; sagittal suture obliterated; 

 no other synostosis. 



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

 ctit; left upper third molar lost, i)robably ante mortem; enamel of teeth not worn; sagittal suture 

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



Vdli/oniiaiix. — No. 1415, small, rather heavy and well-preserved; basilar suture elosed; third 

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

 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 eoiissitied throughout its entire length on the inner table, 

 aiul all but its anterior liftli 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 sjTiostosis. 



No. 1507, small skull; right temi)oral and cerebellar regions broken away; mandible broken 

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

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

 dentine slightly worn. The sagittal is cofissitied 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, Itom a good-sized, rather scaphoid s])ecimen; 

 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-nior 

 tem, is No. 802, 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 o,s epacfale; it is now 

 tirmly coiissified 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. Kather 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 sjaiostotic skulls show this peculiarity except No. 802, 

 which has 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 deeitly wornj 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 its 

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

 brain cajisule. This is probably the skull of finite an old person. 



No. 7;30, a fairly well-preserved skull from Kentucky with mandible; basilar sutnre 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 globo.se appearance are' concerned, this skull is essentially 

 similar to the Saladoan, II. 17. 



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

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

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



