NO. 1495. 



OBSERVATIONS ON ORANQ SKULLS— HRDLICKA. 



541 



ing the adult stage. In females this sign is much less accentuated and 

 is not to be relied upon. 



By the above distinguishing marks Doctor Abbott's collection is 

 separable into one 3"oung, twelve adolescents, and thirteen adults. 



Among the adolescents the second dentition (82 teeth) is fully com- 

 pleted in ten: while in two (Cat. Nos. 14218:^>, and l-l:220()), the third 

 molars are still wholly in their sockets. Of the adult crania several 

 show signs of aging, but none of advanced senility. 



Sex. — The principal signs which characterize the adult male orang 

 skulls are a relatively greater size of the crania, great canine teeth, 

 and a pronounced sagittal crest; while the jaws, particularly the lower, 

 the malars, zygomatic processes, supraorbital ridges, lambdoid crest, 

 and the face, vault, and base as a whole, are larger and heavier than 

 in the females. Judging by these characteristics, the collection con- 

 tains thirteen male and eleven female skulls; in one specimen (Cat. 

 No. 142184), after repeated examinations, the sex remains doubtful. 



The angle of the lower jaw,'^' which in man is a good sexual character, 

 can not be much relied upon in differentiating oran^" skulls, as will be 

 seen from the foliowino- table: 



Mimdihular (nujle in orang.^. 



The average difference between the two sexes is seen to amount to 

 scarcely 2 degrees, and the ranges of individual variation overlap so 

 greatly as to ])e (juite similar. 



In No. 142184. which liy the size of tlie canines approaches the male 

 but by other characteristics is nearer the female skulls, the angle is 

 114^. In the young specimen (Cat. No. 142171), a female having all 

 the teeth of the first dentition l)ut only the first molars and the left 

 lower lateral incisor of the second dentition, the ano-le measures 112"^. 



« Measured on Broca's mandibular goniometer. 



