184 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



All are of that form called by Broca pterioa in H. Wormian bones complicate their char- 

 acters. 



Of the 11 measurable right pteria the longest is 20"" (the maximum of the group) and the 

 shortest is 5""". Of the 17 measurable left pteria the longest is 18""" and the shortest 3'"™ (the 

 minimum of the group). The average length of the right pteria is 12.90""'; the average of the 

 left, pteria is 11.35; the average of all, 11.96. 



There are but two pteria of less than 8""° in length, a percentage of 6.5, which is smaller than 

 any on Anoutchine's* table except that of the Peruvians, which is 3.4. There is but one pterion 

 which does not exceed 3'"", but with oiu- small total of 28 this gives us a percentage of 3.5. 



On the whole the character of the pterion is of a very high type. 



§ 17. UNIQL-TE SAGITTAL SYNOSTOSIS. 



The presence among the Saladoans of 4 skulls showing unique sagittal synostosis, one of 

 them adolescent, has naturally led us to inquire if an early sagittal synostosis can be a physio- 

 logical characteristic of this people, or if, at whatever age synostosis begins, it affects first the 

 sagittal suture. With this point in mind we have investigated several other series of American 

 skulls with the following results (the description applies solely to the outer table except in cases 

 where the inner is expressly mentioned) : 



Saladoans. — The Saladoans present four cases of unique sagittal synostosis as follows : 



No. H. 15, a fairly well-preserved skull, female; basilar suture closed; third molars cut except 

 left lower ( ?) ; right lower second premolar and first molar shed and alveoli absorbed ; right ujjper 

 third molar decayed away ; the two third molars still visible ; lower right and upper left one only 

 shghtly worn, especially the latter; premolars and first molars worn just into the enamel. Sagit- 

 tal suture completely obliterated ; no other synostosis. A line of porosity across the pre-occipital 

 may possibly indicate previous existence of an os epactale. 



No. H. 17, a well-preserved skull of a youth; basilar suture open; all milk teeth shed; no third 

 molars cut; no permanent teeth lost ante-mortem; enamel of first molars a little worn; entire 

 obliteration of sagittal suture; no other synostosis of brain capsule. 



No. H. 45, a fairly well-preserved female skull; basilar suture closed; full set of permanent 

 teeth cut and none of them lost ante-mortem; wear of enamel very slight; complete sagittal oblit 

 eration ; no other synostosis. 



No. H. 49, a much warped and laterally flattened skull; post-mortem distortion; basi-occipital 

 broken away; full set of teeth, except lower third molars, cut and none shed ante-mortem; lower 

 third molars point forward and are impacted against second molars, probably never would have 

 been erupted through gum; first molars worn, but not into dentine; obliteration of sagittal suture; 

 probably no other .synostosis ; sutures of cranial vault all very simple. 



Peruvians. — Among the Peruvians the following cases are to be noted in connection with sag- 

 ittal synostosis: 



No. 2315, a well-preserved skull without mandible; basilar suture closed; permanent teeth all 

 erupted and none lost ante-mortem; all teeth lost post-mortem except left upper first premolar and 

 molar; these teeth worn into the dentine; posterior two-thirds of sagittal suture obliterated; 

 anterior third ossified in spots; no other synostosis; there is a slight ridge about the anterior part 

 of the sagittal suture; the left temporal sends a process to join the frontal bone. 



No. 2506, a well-preserved skull without mandible; basilar suture closed; teeth all cut, but 

 third molars lost ante-mortem; all teeth which are present are worn down to the dentine; complete 

 sagittal obliteration; a very little commencing synostosis of the lambdoid and left occipitomastoid 

 sutures; no other synostosis; sagittal ridge; a process joins right temporal and frontal. 



No. 2945, a well preserved skull with mandible ; basilar suture closed; all permanent teeth 

 cut; both upper third molars and left lower third molar shed ante-mortem; teeth worn down to 

 the dentine; complete obliteration of sagittal and complete obliteration of right squamous suture; 

 no other synostosis ; sagittal ridge. 



'Anoutchine: Sur quelques anomalies du crAne liumain et de lenr fiv^quence dans les races. Eeview by C. de 

 M(5rejkowsky in Kevue d'Anthropologie, 2d series, vol. 5 (1882), p. 359, et. seq. 



