NO. 1495. 



OBSERVATIONS ON ORANG SKULLS— HRDLICKA. 



547 



cavity. The maximum of the protrusion is reached with the comple- 

 ion of the second dentition; and contrary to what is observed in man, 

 but in accord with the differences in the size of the teeth, the prog- 

 nathism is generally greater in the male. The next table gives the 

 gnathic index of the various skulls, obtained bj" the method of Flower 

 /basi-alveolar length X 100^ 



The most prognathic female, it is seen, just reaches the grade of 

 facial protiusion observed in the least prognathic male. It will also 

 be observed that the males show again a greater variation. 



OrljlU. — The orbits are, with one single exception, all of greater 

 height than breadth. The rare, if not unique exception in orangs, is 

 the right orbit of No. 142196, the index of which is 98.6, approaching 

 the megaseme orbits of human crania; the right orbit shows in general 

 a slight tendency to an excess over the left in breadth combined with a 

 defect in height. The same phenomena is present in man, where it is 

 accompanied Ity, and probably stands in some connection with, a percep- 

 tibl}^ greater obliquity of the right palpebral fissure. The average 

 orbital index does not differ much in the two sexes, especially after 

 full growth. The two extremes of shape among the females occur in 

 the two youngest specimens. Both the index and the absolute propor- 

 tions show a large range of individual variation. 



